Mercer County Jail Information

Mercer County Jail | 55 Thompson Road | Mercer, PA 16137 | (724) 662-2700

Mercer County Jail

The modern Mercer County Jail, located on Thompson Road in Mercer, opened in 2005. Mercer County is at the western border of Pennsylvania. The county has 3 cities, 14 boroughs and 31 townships. The borough of Mercer is the county seat. The county and borough are named for Brig. Gen. Hugh Mercer, a Revolutionary War hero and personal friend of George Washington. Mercer is a diverse county. Its population of approximately 109,000 is evenly distributed among age groups.

The early history of the Mercer County jail is linked to that of the county courthouse. Mercer County was formed in 1800. Initially, court was held in a local tavern. Within a few years, a two-story structure, the first public building in Mercer County, was built. The county jail was on the lower floor; the upper floor doubled as a courtroom and Presbyterian meeting hall. A separate, two-story brick courthouse was completed in 1809.

Later, the county replaced the original jail with a two-story stone and iron building. It was surrounded by an 18-foot-high wall. After it was replaced as a jail, this building, dubbed the "Old Stone Jail" served as a hotel. It still stands as a private home.

A third jail of red brick and sandstone was built between 1866 and 1869. At the time, it was regarded as one of the most advanced jails in Pennsylvania. This two-story, 95- by 67-foot jail was built on the Mercer "Diamond" across the way from the then-new county courthouse (completed in 1867). A striking architectural work, it featured a castle-like central front tower.

The jail was extensively remodeled and altered during the 20th Century. In the 1970s, the county built a new jail just to the east of it on South Diamond Street. The old one became part of the courthouse complex, housing county government offices.