Connecticut's 2022 Geographic Reorganization and FIPS Codes
In 2022, Connecticut replaced its 8 historical counties with 9 planning regions for federal statistical purposes. Here's what changed and why it matters for data work.
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.
More Articles
How County Boundary Changes Affect FIPS Codes
County boundaries and names occasionally change, and FIPS codes change with them. Here's a history of major US county FIPS code changes and how to handle them in data work.
Jun 2, 2026
FIPS Codes vs ZIP Codes: Key Differences for Data Work
ZIP codes and FIPS codes both identify US geography, but they serve very different purposes. Here's what every data analyst needs to know.
Nov 27, 2025
USDA Rural Classifications and FIPS Codes
The USDA's Rural-Urban Continuum Codes classify every US county on a 9-point scale from dense metro to completely rural. Here's how they use FIPS codes.
Feb 11, 2026