Westmoreland County, Pennsylvania Population (2025)

Current Population

349,324

Estimated July 1, 2025

-4,946 residents(-1.4%)since 2020

Latest Official Census

354,663

2020 Census

Population Over Time

Estimated population changed from 354,270 in 2020 to 349,324 in 2025.

Annual population estimates by year.
Year	Population	Change	% change
2020	354,270	—	—
2021	353,695	-575	-0.2%
2022	351,924	-1,771	-0.5%
2023	351,233	-691	-0.2%
2024	350,473	-760	-0.2%
2025	349,324	-1,149	-0.3%

2020 Census (official count): 354,663

Sources & Methodology

The current population figure is an annual estimate from the U.S. Census Bureau's Population Estimates Program. The 2020 Census is shown separately as the official benchmark.

Current estimate — 349,324 · July 1, 2025

U.S. Census Bureau — County Resident Population Estimates (CO-EST2025-ALLDATA), Vintage 2025

Official Census — 354,663 · April 1, 2020

U.S. Census Bureau — 2020 Census Redistricting Data (P.L. 94-171), table P1 — county totals (SUMLEV 050)

These figures can differ because the Census and annual population estimates are produced at different times using different methods. Both are shown so you can distinguish the most current estimate from the official Census benchmark.

How the change since 2020 is calculated

Both endpoints come from the same Census Bureau Population Estimates Program release, so the comparison is like for like: 354,270 on July 1, 2020 and 349,324 on July 1, 2025. The change is the later estimate minus the earlier one (-4,946), and the percentage is that change divided by the 2020 estimate (-1.4%). The Decennial Census count is never used as an endpoint here — it is an enumeration on a different reference date, produced by a different method, so subtracting one from the other would measure the difference between two methods as well as the change in population.

U.S. Census Bureau — County Resident Population Estimates (CO-EST2025-ALLDATA), Vintage 2025

Incorporated places in Westmoreland County

44 incorporated places