ct-data-collaborative / ct-census-block-to-town

2010 and 2020 Census Block to Town Crosswalk for Connecticut

Connecticut 2010 and 2020 Census Block to Town Crosswalk

This repository contains crosswalks between CT census blocks (smallest geographical units used by the US Census) and towns in Connecticut for 2010 and 2020 Census. Files are available in CSV and Excel formats.

• The 2010 crosswalk (2010/block2town-2010.csv) contains 67,578 blocks.
• The 2020 crosswalk (2020/block2town-2020.csv) contains 49,926 blocks.

block_fips	block_name	town	county	town_fips
090076802001017	Block 1017	Middletown	Middlesex	0900747360
090010431002040	Block 2040	Norwalk	Fairfield	0900156060
090012201001014	Block 1014	New Fairfield	Fairfield	0900150860
090010431002026	Block 2026	Norwalk	Fairfield	0900156060
090093511001000	Block 1000	Waterbury	New Haven	0900980070
090076101001036	Block 1036	Clinton	Middlesex	0900715350

To prevent Excel from transforming FIPS codes to numbers automatically (which leads to missing leading 0s), do the following:

1. Open Excel, New workbook
2. Go to File > Import > CSV file
3. Choose file, and select "text" as type of block_fips and town_fips columns

How it was generated

In QGIS, open census block boundaries, generate a random point inside polygon (use Point on surface function, not centroid to ensure they fall within town boundaries), and perform nearest neighbor spatial join (NNJoin plugin) to assign the "nearest" town.

Source datasets

• 2020 TIGER/Line Shapefiles: https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.2020.html

License

Released under MIT license. Feel free to use for any project. We will appreciate if you credited CTData Collaborative, although this is not required.