Connecticut's 2022 Geographic Reorganization and FIPS Codes

In 2022, Connecticut made a major change to its county-level geography that affects anyone working with federal datasets for the state. Connecticut's 8 historical counties — established in 1666 and long used for statistical purposes despite having no actual county government — were replaced with 9 planning regions as the state's county-equivalent geographic units for federal data. The new planning regions have new 5-digit FIPS codes in the 09XXX range, replacing the old 8-county codes.

The old Connecticut counties (09001 Fairfield, 09003 Hartford, 09005 Litchfield, 09007 Middlesex, 09009 New Haven, 09011 New London, 09013 Tolland, 09015 Windham) are no longer the primary county-equivalent geography for federal statistical programs. The new 9 planning regions have codes 09110 through 09190. Most federal datasets began using the new codes starting with 2022 data, meaning any analysis spanning pre- and post-2022 requires a crosswalk between the old and new geographies.

This change directly affects Census ACS data, BLS employment data, EPA environmental data, and any other federal dataset that uses Connecticut county-level geography. If you're building a time series for Connecticut counties that extends from, say, 2018 to 2024, you'll hit a discontinuity in 2022 where the geographic units change. The Census Bureau publishes a crosswalk showing which old counties map to which new planning regions, but the mapping isn't always clean — some old county areas were split across new planning regions.

For current Connecticut data, use the 9 new planning region FIPS codes (09110–09190). For historical data, use the 8 old county codes (09001–09015). Our FIPS database reflects the current standard (the 9 planning regions are in the OMB 2023 delineation for MSA membership, though Connecticut's MSA assignments have also been updated). Use Connecticut's state page to browse current county-equivalent geography, and see the FIPS explainer for context on how geographic changes are handled.