United States/Boundaries
The borders of the United States and those of its political subdivisions are represented by administrative boundary relations. The usually-paired tags boundary=administrative and admin_level=* are applied to these relations (and often their member ways, for software compatibility reasons) to indicate their relative level in a political hierarchy. Additionally, border_type=* was and is used inconsistently on land boundaries, largely due to import legacies. However, on maritime borders with specifically-defined values, border_type=* is used consistently. In early 2024, three states (Maine, New Hampshire, Vermont) began to use border_type=* more carefully to denote distinctions between incorporated and unincorporated polygons.
Renderers typically display these boundaries as dashed or dotted lines and may use boundary relations for other purposes, such as to display state-appropriate highway shields. Geocoders use the boundary relations to identify places and construct full addresses. For debugging purposes, this rendering is recommended.
This article is a basic tagging guide for U.S. admin_level=2, 4, 5, 6, 7, 8, 9, 10. It discusses tagging practices that either are already in wide use in OSM or have achieved consensus through the proposal process. In the interest of clarity, this article does not discuss novel tagging proposals. There are numerous exceptions to the information below, some of them quite significant, but this article ignores them in order to focus on how to tag new features as they come up. For a more detailed explanation of governmental structures described in this article, see United States admin level and Wikipedia's series on U.S. Political divisions.
Summary
The following table contains generalizations meant to reflect current usage in OSM.
If you don't see an entry corresponding to the kind of boundary=administrative you are trying to map, consult the corresponding section for more details. If the section doesn't say how to tag the boundary either, it could be that similar boundaries have yet to be mapped, or perhaps the community has yet to reach consensus on how to tag them. In that case, try to be consistent with the entries below when mapping, and let the talk-us mailing list know what you come up with. Again, see United States admin level for more detail.
| 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|
| State or Territory ( state)
|
N/A | County ( county)
|
Civil township ( township)
|
Municipality ( city, village, unincorporated_place)
|
(village,neighbourhood)
|
Neighborhood ( neighbourhood,district)
|
| Alaska | N/A | Borough | N/A | City | N/A | N/A |
| California | N/A | County | N/A | City Town |
Planning Area (sometimes unofficially called "Village," rare, only in Orange County) |
Neighborhood (infrequent, only in larger cities) |
| Connecticut | N/A | Regional Council of Government ¶ ( COG)
|
N/A | Town | City Borough Village |
Neighborhood |
| Florida | N/A | County | N/A* | City Town Village |
N/A | N/A |
| Hawaii | N/A | County | N/A | N/A | N/A | N/A |
| Illinois | N/A | County | Township Precinct |
City Village Town |
N/A | N/A |
| Louisiana | N/A | Parish | N/A | City Town Village |
Ward (rare) | Neighborhood (rare) |
| Maine | N/A | County | N/A | City (city)Town ( town)Plantation (incorporated) ( plantation)Township (unincorporated) ( unincorporated_place)
|
Suburb (of a city) (incorporated) Village (in a township) |
Neighborhood (if there's an organized neighborhood association) |
| Massachusetts | N/A | County | N/A | City Town |
N/A | N/A |
| Michigan | N/A | County | N/A | City | N/A | N/A |
| N/A | County | Township Charter township |
Village | N/A | N/A | |
| Minnesota | N/A | County | Township Town |
City | N/A | Neighborhood |
| Nebraska | N/A | County | Township Precinct |
City Village |
N/A | N/A |
| New Hampshire | N/A | County | N/A | City Town Township ( unincorporated_place)Organized Gore ( unincorporated_place)Grant ( unincorporated_place)Purchase ( unincorporated_place)Location ( unincorporated_place)
|
Ward (only in City) | N/A |
| New Jersey | N/A | County | N/A | Borough City Town Township Village |
N/A | N/A |
| New York | New York City † | County | Borough | N/A | N/A | Community District |
| N/A | County | N/A | City Hamlet |
N/A | N/A | |
| N/A | County | Town | Village | N/A | N/A | |
| Ohio | N/A | County | Township | City Village |
N/A | Neighborhood |
| Oregon | N/A | County | N/A | City Village |
N/A | Neighborhood |
| Pennsylvania | N/A | County | N/A | City Borough/Boro Township Town (Bloomsburg) |
N/A | Neighborhood (Pittsburgh) Planning Analysis Section (Philadelphia) |
| Rhode Island | N/A | County ( county)
|
N/A | City Town |
Village | N/A |
| Tennessee | Grand Division | County ( county)
|
N/A | City | N/A | N/A |
| Utah | N/A | County | Metro Township | City Town |
N/A | N/A |
| Vermont | N/A | County | N/A | City (city)Town ( town)Township ( unincorporated_place)Gore ( unincorporated_place)
|
District (of City) (incorporated) Village (of Town) |
Ward (of District) |
| Virginia | N/A | Independent city ( city)
|
N/A | N/A | N/A | N/A |
| N/A | County | N/A | Town | N/A | N/A | |
| West Virginia | N/A | County | District | City Town Village |
N/A | N/A |
| Wisconsin | N/A | County | Town | City Village |
N/A | N/A |
| District of Columbia ‡ | N/A | N/A | N/A | Washington | Ward | Neighborhood |
| American Samoa | N/A | District | County | Village | N/A | N/A |
| Guam | N/A | Village | N/A | N/A | N/A | N/A |
| Northern Mariana Islands | N/A | Municipality | N/A | N/A | N/A | N/A |
| Puerto Rico | N/A | Municipio (Municipality) | N/A | N/A | Barrio (Ward) | N/A |
| United States Virgin Islands | N/A | District | N/A | Subdistrict | Quarter | Estate |
| United States Minor Outlying Islands § | N/A | N/A | N/A | N/A | N/A | N/A |
National boundary
The federal border is represented by 148838
148838, tagged boundary=administrative admin_level=2 border_type=national. Where this border delineates U.S. territorial waters (e.g., 12 nautical miles off the Atlantic coast, or surrounding minor outlying islands), the member way is tagged border_type=territorial maritime=yes. State and territorial boundary relations are members of this national boundary relation with the role subarea.
You may find some renderers (notably Carto/standard), especially at very wide (global) zoom levels, display certain members of this relation (Alaska's westernmost Aleutian Islands, Guam and Northern Mariana Islands, Wake Island) in a seemingly inconsistent or unusual manner. This is because these areas are west of 180 degrees (the antimeridian): some renderers may require an additional easterly "pan around the globe" to display them.
States in Free Association
The states in Free Association with the USA (Federated States of Micronesia, Marshall Islands and Palau) have national-level admin_level=2 boundary=administratives of their own and are excluded from the United States' national boundary relation. This is because they are sovereign nations in a Compact of Free Association with the United States.
States and Territories
- Main article: United States State Boundary Relations (large table of state and territory relation links).
The borders of states and Territories (including Commonwealths) are tagged boundary=administrative admin_level=4. Some states are additionally tagged border_type=state. As noted below, while the District of Columbia does have an admin_level=4 tag, it is not tagged border_type=state.
Where the border delineates state territorial waters (e.g., 3 nautical miles off the Atlantic coast), the member way is tagged border_type=state maritime=yes. Generally, borders along waterways follow the thalweg (deepest path along the channel). However, state river borders are more nuanced, especially along the Mississippi River and Ohio River, whose banks have changed significantly over the centuries. Do not expect to be able to "eyeball" a state border along a river using aerial imagery.
In Maine, New Hampshire and Vermont, be especially careful to include border_type=* tags, especially on (multi)polygons tagged admin_level=8, as these three states unusually include polygons tagged boundary=administrative which are both incorporated and unincorporated.
Strictly speaking, United States Minor Outlying Islands (USMOI) is not a boundary=administrative, it is a statistical grouping. However, it is convenient, as all eight Pacific islands or island groups plus one (internationally disputed) island in the Caribbean Sea (each of which are territories) are grouped into a single relation. As with the five coastal/ocean states that have boundaries with the Pacific Ocean and the 17 states that have boundaries with the Atlantic Ocean or Gulf of Mexico, each of these islands has U.S. territorial waters as described above, sufficient to delineate the national boundary around USMOI.
Counties, parishes, boroughs, etc.
Boundary relations of political subdivisions of U.S. states known as counties (including Louisiana parishes and Alaska boroughs) are tagged boundary=administrative admin_level=6. Some counties are additionally tagged border_type=county. A county boundary relation's name=* tag should include the word "County" (or "Parish" in Louisiana or "Borough" in Alaska). More county boundary data are available for Georgia, Ohio and Wyoming.
The counties of Connecticut [1] are tagged boundary=administrative + admin_level=6, as Connecticut has government at this level, though it is limited. Similarly, as Rhode Island has very limited county-level governments [2], its counties are also tagged boundary=administrative and admin_level=6, though Rhode Island counties are mostly geographical subdivisions [3]. In Massachusetts, eight of 14 counties have quite limited county-level government and so at one time, did not also have neither boundary=administrative nor admin_level=6 tags on those eight counties. Now (2020) and deliberately by local OSM volunteers, all 14 counties in Massachusetts have both of these tags. So these three states are outliers among 47 other states as "very limited effectively-political counties" (boundary=administrative+ admin_level=6) as these are largely geographical entities.
County boundaries come from USGS data, which are accurate but have lower resolution than other data in OSM.
Outside of the 50 states, and as each of these are "territorial municipalities": districts of U.S. Virgin Islands, municipios of Puerto Rico, villages of Guam, districts and unorganized atolls of American Samoa [4] and islands and an island group in Northern Mariana Islands are tagged admin_level=6, the same as counties in the 50 states. Puerto Rico's municipios and wards were imported from Puerto Rico Planning Board data, while Guam's village data (names end in "Municipality") are from the Census Bureau. A territorial municipality boundary relation's name=* tag should include the word "Municipality" (or one of its flavors: district, municipio, village, unorganized atoll, island or island group).
Civil townships
The Census Bureau infers that Civil townships exist as administrative subdivisions in 21 states. They are usually known as townships or towns (Utah uniquely calls these "metro townships" and there are distinct "charter townships" in Michigan) and are characterized by the fact that they completely subdivide counties (admin_level=6). Hence, civil townships of this kind (including those named "towns") are always tagged boundary=administrative admin_level=7. Depending on the state, it may be possible for a city or village to subordinate to one or more townships, or for a city or village to withdraw from a township, becoming a direct county subdivision. A civil township boundary relation's name=* tag should be prefixed with "Township of" (or "Town of" or "Charter Township of" or "Metro Township of") or suffixed with "Township" (or "Town").
Some states (Maine, New Hampshire, New Jersey, Pennsylvania, Vermont) have administrative subdivisions named "township" but these are not "civil townships" as described here, these are actually city-like, rather than township-like. While this is admittedly confusing, in these five states these should be tagged admin_level=8, not admin_level=7. This decreases the number of states asserted by the Census Bureau (21) by five (to 16) that OSM might agree contain "civil townships."
OSM's TIGER 2005 import omitted minor civil division (MCD) boundaries, including civil townships. Mappers add them manually, often tracing USGS Topographic Maps, where township boundaries are generally shown as black dashed lines. These maps can be slightly misaligned in places, so it helps to switch back to aerial photography once in awhile as a sanity check. If you know the general vicinity of a township line, you may be able to spot a change in pavement quality where one township repaved its road up to the township line.
As mentioned above, except for maritime borders, border_type=* tags suffer from inconsistent application due to legacy imports. Because of this, they have complex semantics on land borders. For what it's worth, you may find border_type=* tagging on townships in several of these 16 states. For example, in Connecticut, New York and Wisconsin, border_type=town tagging is found, while in Indiana, Kansas, Maine, Michigan and Ohio border_type=township tags exist (additionally, border_type=charter_township is found in Michigan). Be aware that in Maine, New Hampshire and Vermont, border_type=* tagging is extant with numerous specific values to denote whether an entity tagged boundary=administrative admin_level=8 is incorporated or unincorporated.
Municipalities
- Main article: United States municipalities
Municipalities are known by many names, such as city, town, township (be careful, see Civil townships above), village, and hamlet. Especially as it is known in the fifty states as "incorporated," tag a municipality with boundary=administrative admin_level=8 and perhaps an appropriate border_type=* tag, such as border_type=city. (In some New England states, "village" might be better tagged with admin_level=9, check the table above). In rare cases and in Maine, New Hampshire and Vermont, an unincorporated community may have well-defined borders that justify a polygon or boundary relation tagged boundary=administrative, but it usually suffices to tag these with a place=* node.
A consolidated city-county is mapped as two separate, coterminous boundaries, one for the city (admin_level=8) and the other for the county (admin_level=6), though some are only tagged with admin_level=6 perhaps also border_type=county;city. On the other hand, an independent city — that is, a city independent of any county — should be mapped as a single boundary=administrative admin_level=6 perhaps also tagged border_type=city.
In some states, it is possible for a city government to own property outside the city limits that is not considered part of the city. For example, a city may own a park or airport that lies within a suburb or unincorporated area. If this is the case and the property is not considered to be an exclave, then omit the property from the boundary and use the ownership=* and operator=* tags to indicate ownership and who operates the property (respectively).
Municipal boundaries were imported from TIGER 2005 shapefile data, which is often very high resolution but contains many inaccuracies. The USGS Topographic Maps layer may be a useful resource for realigning municipal boundaries. However, the distinction between municipal boundaries and civil township boundaries on these USGS maps is not always clear. And unlike civil townships, municipal boundaries are far more likely to change over time due to annexation, so a USGS layer may be outdated with respect to city limits.
See the section "Counties, parishes, boroughs, etc." for information on municipalities or municipios in U.S. territories, which are not equivalent to municipalities in states. These "territorial municipalities," which go by several different names, are always admin_level=6, never admin_level=8.
Municipal subdivisions
Medium-sized and large cities may have formal subdivisions, variously called neighborhoods, districts, boroughs or wards. Where these subdivisions serve as a system of general-purpose units of government with well-defined boundaries, they are tagged boundary=administrative admin_level=10. In some cities, these subdivisions may correspond to voting districts, but this is not necessarily always true. In cities which contain both wards and neighborhoods, it may make sense to tag the wards admin_level=9 and the neighborhoods admin_level=10, to preserve this hierarchy. However, if a ward is only distinguished for electoral purposes, tag it as boundary=political political_division=ward.
For example, each neighborhood of Cincinnati, Ohio, has a semiformal neighborhood council, and the neighborhood boundaries are well-known. By contrast, many of the neighborhoods of San Jose, California, are amorphous, so they are instead mapped as place=suburb nodes. Naturally, there is much gray area between these extremes, so use common sense. If boundaries of a neighborhood are subjective and impossible to verify using signage alone, chances are the neighborhood is better mapped as a node. Especially when tagged as nodes, such smaller, named place=*s or populated areas inside of larger cities have a distinct method of tagging (e.g. place=suburb, place=quarter, place=neighbourhood...): see place=* and United_States/Tags#Places for details.
Examples of cities with formal subdivisions include Chicago, Illinois; Cincinnati, Ohio; Cleveland, Ohio; Minneapolis, Minnesota; Seattle, Washington; Tucson, Arizona; and Washington, D.C. In Washington, D.C., "neighborhoods" are entered both as nodes and as polygons tagged boundary=administrative admin_level=10, the nodes appear to be "improving towards" polygons.
Areas of New England have state-specific idiosyncrasies regarding "towns" and "villages" which are subordinate to counties and cities (not necessarily respectively). Be careful with these and check the table for what are believed to be the current best tagging strategies. However, if you believe the structure in the table needs updating, please use the Discussion page.
In smaller-sized cities, especially suburbs (not in the OSM sense, but in the US English sense of "smaller incorporated city near a large city"), consider mapping (sometimes homeowner association–managed) residential subdivisions with landuse=residential ways (often closed polygons). If there is no particular management but there is a clearly named or signed identity to a residential subdivision, a landuse=residential tag on ways (often closed-way polygons), plus a name=* tag suffices. (Omit admin_level=*). On the other hand, some planned communities such as The Woodlands, Texas have a formal system of named subdivisions, which could be mapped with type=boundary, but actually are mapped with landuse=residential polygons.
Capitals of administrative regions
Boundary relations should normally include a place node, as follows:
- For the United States, the national capital place node for Washington, DC is tagged capital=2 and with role
admin_centre - For each state or territory, the state or territorial capital is tagged capital=4 and with role admin_centre
- For each county which has a county seat, the county seat place node is tagged capital=6 and with role admin_centre
- For all other administrative boundaries, a place node representing the most significant center of population is attached wth role label
Notable exceptions
- ‡ Washington, D.C., like most city-level municipal boundaries, is tagged admin_level=8, while the coterminous District of Columbia is tagged admin_level=4. As the Census Bureau considers Washington a statistical "county equivalent" (similar to a Consolidated City County, but not one), there might also be a third coterminous relation tagged admin_level=6. However, OSM consensus is that "Washington, District of Columbia" is only these two relations (tagged admin_level=8 and admin_level=4, respectively). Washington also has wards (admin_level=9) and neighborhoods (admin_level=10). It is correct that the District is not tagged border_type=state as it is a national district, not a state.
- ¶ RCOGs are denoted as administrative in admin_level=*'s sense with border_type=COG as an OSM convention and as agreed to by the Census Bureau as statistical "county-equivalents." County is no longer tagged admin_level=6, as even though counties delineate judicial districts, these are tagged border_type=county with no admin_level=* tag.
- * The Central Florida Tourism Oversight District in Florida, near Walt Disney World, is tagged admin_level=7 due to unusual history. In a state of flux in 2024 (Disney v. DeSantis litigation). Due to a "perpetuity clause," the District may be around in a certain legal sense apparently as long as the current King of England's grandchildren, now "no legal standing." Stay tuned.
- † The New York City boundary relation is tagged admin_level=5 by OSM consensus. It fully and exactly encompasses five county-level (admin_level=6) boroughs, tagged admin_level=7. Boroughs are coterminous with counties, each for specific government administrations. Both (five counties at 6, five boroughs at 7) are entered into OSM as New York City (5).
- § United States Minor Outlying Islands is a statistical area, not tagged admin_level=4: it suffices that each island is U.S. territory surrounded by territorial waters, delineated with admin_level=2. Let's keep the relation as a convenient grouping.
Other types of boundaries
- For Native American Indian reservations, see United_States/American_Indian_reservations, United_States_admin_level#Native_American_Indian_reservations and United_States_admin_level#Townships,_some_Districts,_Agencies..._as_divisions_of_Native_American_Nations.
- Census-designated places (CDPs) are statistical, not administrative areas. Project TIGER fixup deletes outdated CDPs and retags relevant ones from boundary=administrative admin_level=8 (or 7, or 9) to boundary=census, no admin_level=*. Be careful with CDPs in Alaska, as these are areas which are agreed upon between the Census Bureau and the state of Alaska to be used by both levels of government as possible or actual administrative areas. Still, these should be tagged with boundary=census, no admin_level=*, just as any census area in the USA.
- ZIP codes are not boundaries at all: they are more like routing algorithms to expedite mail delivery.
Other uses of admin_level
The admin_level=* values described above also apply to the following tags:
- capital=* – A national capital is tagged capital=yes, though a state capital is tagged capital=4 and a county seat is tagged capital=6.
- heritage=* – For example, a National Historic Landmark is tagged heritage=2, signifying that its historical status is registered with the national-level National Register of Historic Places. There are State Historic Landmarks designated by a state-level Register of Historic Places, these are tagged heritage=4.
There is Proposed_features/Key:park:public_level which proposes to assign a value of admin_level appropriate to the administrative level of governmemt of a public park to "parks," as that word is meant in the USA (not necessarily as the strict definition in leisure=park). For example, a "county park" might be tagged park:public_level=6.