Mercer

Formed January 22, 1800 (27^th county)

Mercer County (110,656), Mercer (1,985), Hermitage (16,231)

The 1909 Classical Revival structure is made of red brick.  The building is at the intersection of Diamond and Erie streets.  Erie Street is United States Highway 19.  Charles F. Owsley is the courthouse designer.  An Annex supports the courthouse.  There was an 1866 version earlier in Mercer, the only county seat.  The county was created on January 22, 1800 from Allegheny County as the 27^th county.  Mercer County and its county seat are named for Doctor Hugh Mercer, from the American Revolutionary War. 

Mercer County government consists of a sheriff and 3 Commissioners.  Seven Common Pleas Court Judges and Three Magistrate Court Judges serve Mercer County.  Mercer County is on the western border with Ohio.  Erie, Pennsylvania is north and Pittsburgh, Pennsylvania is southeast of the county.  The county center is 6.5 miles Northwest of Mercer nearer Fredonia.  The county is surrounded clockwise by Crawford, Venango, Butler, and Lawrence counties and Ohio. 

The area of the county is 683 square miles.  It is 32 out of 67 in the state.  It ranks 30 out of 67 in population in the state.  It has a density of 162.0 persons per square mile making it 31 out of 67 in the state.  Mercer County has 52.8% of its population in its incorporated areas.  Interstate Highway 79 travels through the county from north to south from Crawford County to Lawrence County.  Interstate Highway 80 goes east to west from Venango County to Ohio.  United States Highway 19 parallels Interstate Highway 79 from Crawford to Lawrence counties.  United States Highway 62 enters from Venango County, east, and exits to Ohio, west.  The county is an overall rectangle with a spike on the southeast corner.  The City of Mercer is located in the southern quarter of the county.  Hermitage is in the southwest quarter of the county.  Mercer is the county seat and Hermitage is the largest city.  Mercer is 1.8% of the county population while Hermitage is 14.7% of the county population.  This county is in the Youngstown-Warren-Boardman Metropolitan Statistical Area.