Population Of Pennsylvania 2025. Montgomery county (820,656), bucks county (626,751), and delaware county (563,995) are all in the top five most populous counties in the state, and census statistics show. In the preceding decade, from 2010 to 2020, the state's population.
The population of pennsylvania in 2023 was 12,961,683, a 0.08% decline from. The pennsylvania independent fiscal office (ifo) projected, in october.