Selinsgrove is a borough in Snyder County , Pennsylvania , United States . It was founded in 1787 by Captain Anthony Selin, who fought with Washington in the Revolutionary War. The population was 5,383 at the 2000 census. More specifically in terms of demographics the number of men in Selinsgrove is 2,357, and the number of women is 3,026. It is the largest borough in Snyder County. Nestled in the middle of the Susquehanna River Valley in Central Pennsylvania, Selinsgrove is located along US Route 11 & US Route 15 , 50 miles north of Harrisburg and about five miles southwest of Sunbury .
History Selinsgrove was founded in 1787 by Captain Anthony Selin, who fought with George Washington in the American Revolution . Occurring on October 16, 1755, the Penns Creek Massacre was the first Indian hostility event in the region after General Braddock's defeat in Seven Year War. A marker on the bank of Penns Creek north of Selinsgrove, Pennsylvania, commemorates the massacre of settlers by Native Americans, with fourteen killed and eleven taken captive. The Leroy Massacre site is about 2 km southeast of Mifflinburg, Pennsylvania . Near here, John Jacob Leroy was killed by Indians on 16 October 1755, following the Penn's Creek Massacre. In response, Conrad Weiser organizes local defence. Fort Augusta at Shamokin now Sunbury, Pennsylvania , the largest of Pennsylvania's frontier forts, was built in 1756 as a result of this conflict. Routes 11 & 15 once traversed the borough by its primary artery, Market Street. Traffic concerns led to the construction of a bypass to funnel long haul traffic around the historic downtown. Like many similar projects, an unintended consequence of this bypass was the growth of retail and commercial businesses in the communities north of the borough.