COUNTY · PA
Westmoreland County, Pennsylvania
Westmoreland County is a county in Pennsylvania with FIPS code 42129 and an estimated population of 351,163 (Census 2023), 11th largest of 67 in the state.
County facts
- Name
- Westmoreland County
- State
- Pennsylvania
- Type
- county
- FIPS code
- 42129
- State FIPS
- 42
- Population (2023)
- 351,163
- Change since 2020
- -0.9%
- State rank
- 11 of 67
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Westmoreland County?
Westmoreland County, Pennsylvania has the five-digit FIPS code 42129: 42 for the state and 129 for the county.
What state is Westmoreland County in?
Westmoreland 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.