West Middlesex
- County:
- Mercer County
- County Seat:
- No
- Area (mi²):
- 0.845
- State:
- Pennsylvania
West Middlesex is a borough located in Mercer County, Pennsylvania. West Middlesex has a 2026 population of 794. West Middlesex is currently declining at a rate of -0.5% annually and its population has decreased by -3.05% since the most recent census, which recorded a population of 819 in 2020.
The median household income in West Middlesex is $89,667 with a poverty rate of 1.33%. The median age in West Middlesex is 43.1 years: 43.3 years for males, and 42.1 years for females. For every 100 females there are 107.2 males.