Nemacolin Castle, also known as Bowman's Castle, was built in present-day Brownsville, Pennsylvania, at the western terminus of the Nemacolin's Trail. It was built around the original trading post, which was built near the site of Fort Burd, the latter built by British colonists during the French and Indian War. Construction on the castle, including additions of a crenelated tower, continued through the Victorian era.

Brownsville, PA has the distinct honor of listing two of its districts in the National Register of Historic Places: the downtown Brownsville Historic District and Brownsville's Northside Historic District. These areas includes 315 unique structures inside a two square mile area. Within this boundary, four sites have National Register of Historic Places registration: Nemacolin Castle, the Historic Church of St. Peters, the Dunlap Creek Bridge, and the Intercounty Bridge.

The Castle is one of several buildings of the 1850's (In this case, the site holds part of Fort Burd;the well dug by the Fort Burd soldiers) still standing in western Pennsylvania. It is listed on the National Register of Historic Places.

Its alternate name, Nemacolin's Castle, was derived from Nemacolin's Trail, named after the Shawnee chief who helped improve and mark the ancient Native American trail through the Alleghenies. It connected the valleys of the Potomac River and the Ohio River drainage basin on the Monongahela River.