California County Boundaries and Identifiers

Description

Note: The schema changed in February 2025 - please see below. We will post a roadmap of upcoming changes, but service URLs and schema are now stable. For deployment status of new services beginning in February 2025, see https://gis.data.ca.gov/pages/city-and-county-boundary-data-status. Additional roadmap and status links at the bottom of this metadata.

This dataset is regularly updated as the source data from CDTFA is updated, as often as many times a month. If you require unchanging point-in-time data, export a copy for your own use rather than using the service directly in your applications.

 

 

Purpose
 

County boundaries along with third party identifiers used to join in external data. Boundaries are from the California Department of Tax and Fee Administration (CDTFA). These boundaries are the best available statewide data source in that CDTFA receives changes in incorporation and boundary lines from the Board of Equalization, who receives them from local jurisdictions for tax purposes. Boundary accuracy is *not* guaranteed, and though CDTFA works to align boundaries based on historical records and local changes, errors will exist. If you require a legal assessment of boundary location, contact a licensed surveyor.

This dataset joins in multiple attributes and identifiers from the US Census Bureau and Board on Geographic Names to facilitate adding additional third party data sources. In addition, we attach attributes of our own to ease and reduce common processing needs and questions. Finally, coastal buffers are separated into separate polygons, leaving the land-based portions of jurisdictions and coastal buffers in adjacent polygons. This layer removes the coastal buffer polygons. This feature layer is for public use.

 

Related Layers

This dataset is part of a grouping of many datasets:

  1. Cities: Only the city boundaries and attributes, without any unincorporated areas
  2. Counties: Full county boundaries and attributes, including all cities within as a single polygon
  3. Cities and Full Counties: A merge of the other two layers, so polygons overlap within city boundaries. Some customers require this behavior, so we provide it as a separate service.
  4. City and County Abbreviations
  5. Unincorporated Areas (Coming Soon)
  6. Census Designated Places
  7. Cartographic Coastline
 
Working with Coastal Buffers
 
The dataset you are currently viewing excludes the coastal buffers for cities and counties that have them in the source data from CDTFA. In the versions where they are included, they remain as a second polygon on cities or counties that have them, with all the same identifiers, and a value in the COASTAL field indicating if it"s an ocean or a bay buffer. If you wish to have a single polygon per jurisdiction that includes the coastal buffers, you can run a Dissolve on the version that has the coastal buffers on all the fields except OFFSHORE and AREA_SQMI to get a version with the correct identifiers.

 
 
 

Point of Contact

California Department of Technology, Office of Digital Services, gis@state.ca.gov

 

 

Field and Abbreviation Definitions

  • CDTFA_COUNTY: CDTFA county name. For counties, this will be the name of the polygon itself. For cities, it is the name of the county the city polygon is within.
  • CDTFA_COPRI: county number followed by the 3-digit city primary number used in the Board of Equalization"s 6-digit tax rate area numbering system. The boundary data originate with CDTFA's teams managing tax rate information, so this field is preserved and flows into this dataset.
  • CENSUS_GEOID: numeric geographic identifiers from the US Census Bureau
  • CENSUS_PLACE_TYPE: City, County, or Town, stripped off the census name for identification purpose.
  • GNIS_PLACE_NAME: Board on Geographic Names authorized nomenclature for area names published in the Geographic Name Information System
  • GNIS_ID: The numeric identifier from the Board on Geographic Names that can be used to join these boundaries to other datasets utilizing this identifier.
  • CDT_COUNTY_ABBR: Abbreviations of county names - originally derived from CalTrans Division of Local Assistance and now managed by CDT. Abbreviations are 3 characters.
  • CDT_NAME_SHORT: The name of the jurisdiction (city or county) with the word "City" or "County" stripped off the end. Some changes may come to how we process this value to make it more consistent.
  • AREA_SQMI: The area of the administrative unit (city or county) in square miles, calculated in EPSG 3310 California Teale Albers.
  • OFFSHORE: Indicates if the polygon is a coastal buffer. Null for land polygons. Additional values include "ocean" and "bay".
  • PRIMARY_DOMAIN: Currently empty/null for all records. Placeholder field for official URL of the city or county
  • CENSUS_POPULATION: Currently null for all records. In the future, it will include the most recent US Census population estimate for the jurisdiction.
  • GlobalID: While all of the layers we provide in this dataset include a GlobalID field with unique values, we do not recommend you make any use of it. The GlobalID field exists to support offline sync, but is not persistent, so data keyed to it will be orphaned at our next update. Use one of the other persistent identifiers, such as GNIS_ID or GEOID instead.

 

Boundary Accuracy
County boundaries were originally derived from a 1:24,000 accuracy dataset, with improvements made in some places to boundary alignments based on research into historical records and boundary changes as CDTFA learns of them. City boundary data are derived from pre-GIS tax maps, digitized at BOE and CDTFA, with adjustments made directly in GIS for new annexations, detachments, and corrections.

Boundary accuracy within the dataset varies. While CDTFA strives to correctly include or exclude parcels from jurisdictions for accurate tax assessment, this dataset does not guarantee that a parcel is placed in the correct jurisdiction. When a parcel is in the correct jurisdiction, this dataset cannot guarantee accurate placement of boundary lines within or between parcels or rights of way. This dataset also provides no information on parcel boundaries. For exact jurisdictional or parcel boundary locations, please consult the county assessor's office and a licensed surveyor.

 
CDTFA's data is used as the best available source because BOE and CDTFA receive information about changes in jurisdictions which otherwise need to be collected independently by an agency or company to compile into usable map boundaries. CDTFA maintains the best available statewide boundary information.
 

 

CDTFA's source data notes the following about accuracy:

 

City boundary changes and county boundary line adjustments filed with the Board of Equalization per Government Code 54900. This GIS layer contains the boundaries of the unincorporated county and incorporated cities within the state of California. The initial dataset was created in March of 2015 and was based on the State Board of Equalization tax rate area boundaries. As of April 1, 2024, the maintenance of this dataset is provided by the California Department of Tax and Fee Administration for the purpose of determining sales and use tax rates. The boundaries are continuously being revised to align with aerial imagery when areas of conflict are discovered between the original boundary provided by the California State Board of Equalization and the boundary made publicly available by local, state, and federal government. Some differences may occur between actual recorded boundaries and the boundaries used for sales and use tax purposes. The boundaries in this map are representations of taxing jurisdictions for the purpose of determining sales and use tax rates and should not be used to determine precise city or county boundary line locations. 
 

 

 

 

Boundary Processing
These data make a structural change from the source data. While the full boundaries provided by CDTFA include coastal buffers of varying sizes, many users need boundaries to end at the shoreline of the ocean or a bay. As a result, after examining existing city and county boundary layers, these datasets provide a coastline cut generally along the ocean facing coastline. For county boundaries in northern California, the cut runs near the Golden Gate Bridge, while for cities, we cut along the bay shoreline and into the edge of the Delta at the boundaries of Solano, Contra Costa, and Sacramento counties.

 
In the services linked above, the versions that include the coastal buffers contain them as a second (or third) polygon for the city or county, with the value in the COASTAL field set to whether it"s a bay or ocean polygon. These can be processed back into a single polygon by dissolving on all the fields you wish to keep, since the attributes, other than the COASTAL field and geometry attributes (like areas) remain the same between the polygons for this purpose.

 
 
 
Slivers
In cases where a city or county"s boundary ends near a coastline, our coastline data may cross back and forth many times while roughly paralleling the jurisdiction"s boundary, resulting in many polygon slivers. We post-process the data to remove these slivers using a city/county boundary priority algorithm. That is, when the data run parallel to each other, we discard the coastline cut and keep the CDTFA-provided boundary, even if it extends into the ocean a small amount. This processing supports consistent boundaries for Fort Bragg, Point Arena, San Francisco, Pacifica, Half Moon Bay, and Capitola, in addition to others. More information on this algorithm will be provided soon.

 
 
Coastline Caveats
Some cities have buffers extending into water bodies that we do not cut at the shoreline. These include South Lake Tahoe and Folsom, which extend into neighboring lakes, and San Diego and surrounding cities that extend into San Diego Bay, which our shoreline encloses. If you have feedback on the exclusion of these items, or others, from the shoreline cuts, please reach out using the contact information above.

 
 
Offline Use
This service is fully enabled for sync and export using Esri Field Maps or other similar tools. Importantly, the GlobalID field exists only to support that use case and should not be used for any other purpose (see note in field descriptions).
 
 
Updates and Date of Processing
Concurrent with CDTFA updates, approximately every two weeks, Last Processed: 03/01/2025 by Nick Santos using code path at https://github.com/Office-of-Digital-Services/gis-city-county at commit 1ecb474343f85747bdf106dbefac1ed18809f23b. It incorporates updates from CDTFA as of 02/21/2025. Future updates will include improvements to metadata and update frequency.

 
Software, Changes, Issues, and Roadmap
The code that builds and deploys this dataset is a work in progress and receives updates that change data, features, metadata, and more. To contribute a change, please reach out to the email address above or see the links below:
  1. Software repository
  2. File an issue, request a change, or report a problem
  3. Service deployment status page
  4. Software roadmap

Resources

Name Format Description Link
21 https://gis.data.ca.gov/datasets/California::california-county-boundaries-and-identifiers
3 https://services3.arcgis.com/uknczv4rpevve42E/arcgis/rest/services/California_County_Boundaries_and_Identifiers_Blue_Version_view/FeatureServer/1
8 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/csv?layers=1
57 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/shapefile?layers=1
15 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/geojson?layers=1
25 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/kml?layers=1
57 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/filegdb?layers=1
47 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/featureCollection?layers=1
53 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/excel?layers=1
0 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/geoPackage?layers=1
0 https://gis.data.ca.gov/api/download/v1/items/60b7e0f3d33b4064a4b43bf14589bfe3/sqlite?layers=1

Tags

  • california-department-of-technology
  • boundaries
  • county

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