COUNTY · PA
Jefferson County, Pennsylvania
Jefferson County is a county in Pennsylvania with FIPS code 42065 and an estimated population of 43,612 (Census 2023), 48th largest of 67 in the state.
County facts
- Name
- Jefferson County
- State
- Pennsylvania
- Type
- county
- FIPS code
- 42065
- State FIPS
- 42
- Population (2023)
- 43,612
- Change since 2020
- -2.0%
- State rank
- 48 of 67
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Jefferson County?
Jefferson County, Pennsylvania has the five-digit FIPS code 42065: 42 for the state and 065 for the county.
What state is Jefferson County in?
Jefferson County is in Pennsylvania.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.