Founded in 1800, Mercer County is one of 67 counties in the state of Pennsylvania. Historically, Mercer County was formed from parts of Allegheny County. The city of Mercer is the county seat. With FIPS code of 85, Mercer County has a population of 109,972 and area of 683 square miles (1,769 km2).
List of all cities in Mercer County, PA alphabetically
| City/Town | Postal Code | Area Code |
| Carlton, PA | 16311 | 814 |
| Clark, PA | 16113 | 724/878 |
| Clarks Mills, PA | 16114 | 724/878 |
| Delaware Township, PA | 16154 | 724/878 |
| Farrell, PA | 16121 | 724/878 |
| Fredonia, PA | 16124 | 724/878 |
| Greenville, PA | 16125 | 724/878 |
| Grove City, PA | 16127 | 724/878 |
| Grove City Postal Retail Str, PA | 16127 | 724/878 |
| Hadley, PA | 16130 | 724/878 |
| Hermitage, PA | 16148 | 724/878 |
| Jackson Center, PA | 16133 | 724/878 |
| Jamestown, PA | 16134 | 724/878 |
| Mercer, PA | 16137 | 724/878 |
| Sandy Lake, PA | 16145 | 724/878 |
| Sharon, PA | 16146 | 724/878 |
| Sharon, PA | 16148 | 724/878 |
| Sharpsville, PA | 16150 | 724/878 |
| Sheakleyville, PA | 16151 | 724/878 |
| Shenango, PA | 16125 | 724/878 |
| South Pymatuning Township, PA | 16154 | 724/878 |
| Stoneboro, PA | 16153 | 724/878 |
| Transfer, PA | 16154 | 724/878 |
| West Middlesex, PA | 16159 | 724/878 |
| Westford, PA | 16134 | 724/878 |
| Wheatland, PA | 16161 | 724/878 |