Mercer County
Ceir sawl sir o'r enw Mercer County yn yr Unol Daleithiau, gan gynnwys:
- Mercer County, New Jersey
- Mercer County, Illinois
- Mercer County, Kentucky
- Mercer County, Missouri
- Mercer County, Gogledd Dakota
- Mercer County, Ohio
- Mercer County, Pennsylvania
- Mercer County, Gorllewin Virginia