King County GIS Center
King Street Center
201 S. Jackson St.
Suite 706
Seattle, WA 98104

+ 47.59909 N
- 122.33136 W

+ 47°  35' 56.72"
- 122° 19' 52.90"


2020 Census Block Groups for King County

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image


Layer name: BLKGRP20
Subject category: census
Title: 2020 Census Block Groups for King County
Feature Count: 1545
Feature Type: Polygon
Abstract: This layer contains a geographic identifier (GEO_ID_GRP) for each block group that is the key field for the data from censuses and surveys such as Decennial Census, Economic Census, American Community Survey, and the Population Estimates Program. Data from many of the Census Bureau’s surveys and censuses, are available at the Census Bureau’s public data dissemination website ( All original TIGER/Line shapefiles and geodatabases with demographic data are available atThe TIGER/Line Shapefiles are extracts of selected geographic and cartographic information from the Census Bureau's Master Address File (MAF)/Topologically Integrated Geographic Encoding and Referencing (TIGER) Database (MTDB). The shapefiles include information for the fifty states, the District of Columbia, Puerto Rico, and the Island areas (American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the United States Virgin Islands). The shapefiles include polygon boundaries of geographic areas and features, linear features including roads and hydrography, and point features. These shapefiles do not contain any sensitive data or confidential data protected by Title 13 of the U.S.C.Standard block groups are clusters of blocks within the same census tract that have the same first digit of their 4-character census block number (e.g., Blocks 3001, 3002, 3003 to 3999 in census tract 1210.02 belong to block group 3). Current block groups do not always maintain these same block number to block group relationships due to boundary and feature changes that occur throughout the decade. For example, block 3001 might move due to a change in the census tract boundary. Block groups delineated for the 2020 Census generally contain 600 to 3,000 people and a block group usually covers a contiguous area. Each census tract contains one or more block groups and block groups have unique numbers within census tract. Within the standard census geographic hierarchy, block groups never cross county or census tract boundaries, but may cross the boundaries of county subdivisions, places, urban areas, voting districts, congressional districts, and AIANNH areas.Block groups have a valid range of zero (0) through nine (9). Block groups beginning with a zero generally are in coastal and Great Lakes water and territorial seas. Rather than extending a census tract boundary into the Great Lakes or out to the 3-mile territorial sea limit, the Census Bureau delineated some census tract boundaries along the shoreline or just offshore. Full documentation:
Purpose: 2020 United States Census Bureau block group census geography. Converted from Census Bureau TIGER/Line shapefiles and updated to meet King County GIS standards.
Updated: As needed
Time period of content: (single date,as YYYYMMDD)::
Time period of content: (date range, as YYYYMMDD):: -
Spatial reference: WA State Plane North
FGDC Documentation: Classic or FAQ
Open Data Availability: Yes
Place Keywords: Washington state, King County, WA, Pacific NW,
Theme Keywords: census,
Lineage: Not available


Maintained by:
King County GIS Center
Primary: Mary Ullrich, GIS Specialist, 206-477-4420
(How to e-mail a County contact)
Secondary: KCGIS Center; This mailbox is monitored during business hours.

Attribute Information

_STATEFP20_Census Bureau code for a state.
_COUNTYFP20_Census Bureau code for a county.
_TRACTCE20_Census Bureau code for a tract.
_BLKGRPCE20_Census Bureau code for a block group. This is not unique and may appear again in other block groups in neighboring census tracts.
_GEO_ID_GRP_Unique geographic identifier for a block group. Used as the key field to join tabular data from the Census Bureau.
_NAMELSAD20_Block group name
Block Group 0
Block Group 1
Block Group 2
Block Group 3
Block Group 4
Block Group 5
_ALAND20_Land area as calculated by Census Bureau.
Range Min:0.0
Range Max:1058740605.0
_AWATER20_Water area as calculated by Census Bureau.
Range Min:0.0
Range Max:240227879.0
Range Min:2921.30218784
Range Max:720741.019843
_BLKGRP_LBL2_King County label for census block group.


Access: Access Constraint: Data is available on GIS Data Portal:

Use: Use Constraint: King County data are made available with the understanding that they shall be used exclusively by the obtainer or his/her authorized agents. Digital products may not be reproduced or redistributed in any form or by any means without the express written authorization of King County.