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File Format and Record Layouts for the 2010 Census Block Relationship Files

Block relationship files are state-based tabular files. Areal relationships between blocks can be determined by using commercially available GIS software with the Census Bureau's TIGER/Line shapefiles.

These block relationship files identify states and counties by FIPS (Federal Information Processing Series) codes. These files do not include the geographic names referenced by the FIPS codes. Block relationship files are provided in a comma-delimited ASCII text file format. Each type of block relationship file has a separate record layout which are provided below.

Also available in separate text files are the header information for the Census 2000 Tabulation Block to 2010 Census Collection Block, Census 2000 Tabulation Block to 2010 Census Tabulation Block and 2010 Census Collection Block to 2010 Census Tabulation Block relationship files.

Block relationships may be one-to-one, many-to-one, one-to-many, or many-to-many.  The Block Part Flag indicates whether the record for an individual block within any pairing of blocks represents all or a portion of the block.  For instance, in a one-to-one relationship between a 2000 tabulation block and a 2010 collection block, the block part flag for each will be blank, indicating that the tabulation block in its entirety is coextensive with the collection block.  In a many-to-one relationship, multiple tabulation blocks may be contained within one collection block.  In this instance, the block part flag for each tabulation block would be blank; the block part flag for the collection block record in each pair would be “P” since the tabulation block relates to only a portion of the collection block.


Census 2000 Tabulation Block to 2010 Census Collection Block Relationship File Layout

Field # Maximum Length Field Name Field Description
1 2 STATE_2000 2000 tabulation state FIPS code
2 3 COUNTY_2000 2000 tabulation county FIPS code
3 6 TRACT_2000 2000 census tract number
4 4 BLK_2000 2000 tabulation block number
5 1 BLKSF_2000 2000 tabulation block suffix (field is empty)
6 1 BLOCK_PART_FLAG_O 2000 tabulation block part flag; Blank = whole; P = part
7 2 STATE_2010 2010 collection state FIPS code
8 3 COUNTY_2010 2010 collection county FIPS code
9 2 COLTRACTST 2010 collection tract state code
10 3 COLTRACTCOU 2010 collection tract county code
11 6 COLTRACT_2010 2010 collection tract number
12 5 COLBLK_2010 2010 collection block number
13 1 COLBLKSF1_2010 2010 collection block suffix 1 (field is empty)
14 1 COLBLKSF2_2010 2010 collection block suffix 2 (field is empty)
15 1 TEA_2010 2010 type of enumeration area (field is empty)
16 1 BLOCK_PART_FLAG_R 2010 collection block part flag; Blank = whole; P = part

Census 2000 Tabulation Block to 2010 Census Tabulation Block Relationship File Layout

Field # Maximum Length Field Name Field Description
1 2 STATE_2000 2000 tabulation state FIPS code
2 3 COUNTY_2000 2000 tabulation county FIPS code
3 6 TRACT_2000 2000 census tract number
4 4 BLK_2000 2000 tabulation block number
5 1 BLKSF_2000 2000 tabulation block suffix
6 14 AREALAND_2000 2000 Land Area
7 14 AREAWATER_2000 2000 Water Area
8 1 BLOCK_PART_FLAG_O 2000 tabulation block part flag; Blank = whole; P = part
9 2 STATE_2010 2010 tabulation state FIPS code
10 3 COUNTY_2010 2010 tabulation county FIPS code
11 6 TRACT_2010 2010 census tract number
12 4 BLK_2010 2010 tabulation block number
13 1 BLKSF_2010 2010 tabulation block suffix
14 14 AREALAND_2010 2010 Land Area
15 14 AREAWATER_2010 2010 Water Area
16 1 BLOCK_PART_FLAG_R 2010 tabulation block part flag; Blank = whole; P = part
17 14 AREALAND_INT Intersection Land Area shared by the 2000 and 2010 blocks represented by the record
18 14 AREAWATER_INT Intersection Water Area shared by the 2000 and 2010 blocks represented by the record

2010 Census Collection Block to 2010 Census Tabulation Block Relationship File Layout

Field # Maximum Length Field Name Field Description
1 2 COL_STATE_2010 2010 collection state FIPS code
2 3 COL_COUNTY_2010 2010 collection county FIPS code
3 2 COLTRACTST 2010 collection tract state code
4 3 COLTRACTCOU 2010 collection tract county code
5 6 COLTRACT_2010 2010 collection tract number
6 5 COLBLK_2010 2010 collection block number
7 1 COLBLKSF1_2010 2010 collection block suffix 1
8 1 COLBLKSF2_2010 2010 collection block suffix 2
9 1 TEA_2010 2010 type of enumeration area
10 1 BLOCK_PART_FLAG_O 2010 collection block part flag; Blank = whole; P = part
11 2 TAB_STATE_2010 2010 tabulation state FIPS code
12 3 TAB_COUNTY_2010 2010 tabulation county FIPS code
13 6 TRACT_2010 2010 tabulation census tract number
14 4 BLK_2010 2010 tabulation block number
15 1 BLKSF_2010 2010 tabulation block suffix
16 1 BLOCK_PART_FLAG_R 2010 tabulation block part flag; Blank = whole; P = part

Source: U.S. Census Bureau | Geography | (301) 763-1128 |  Last Revised: March 11, 2013