Monaca
- County:
- Beaver County
- County Seat:
- No
- Area (mi²):
- 2.027
- State:
- Pennsylvania
Monaca is a borough located in Beaver County, Pennsylvania. Monaca has a 2026 population of 5,466. Monaca is currently declining at a rate of -0.33% annually and its population has decreased by -2.55% since the most recent census, which recorded a population of 5,609 in 2020.