Lewisburg is a borough in Union County, Pennsylvania, United States, 30mi south by southeast of Williamsport and 60mi north of Harrisburg. In the past, it was the commercial center for a fertile grain and general farming region. The population was 5,620 at the 2000 census. It is the county seat of Union County. Located in central Pennsylvania, on the West Branch Susquehanna River, Lewisburg is northwest of Sunbury. It is home to Bucknell University and is near the Lewisburg Federal Penitentiary. Its 19th-century downtown is on the National Register of Historic Places. Lewisburg is the principal city of the Lewisburg, PA Micropolitan Statistical Area, and is also part of the larger Bloomsburg-Berwick-Sunbury, PA Combined Statistical Area.HistoryLewisburg was founded in 1785 by Ludwig Derr. A settler of the area (since as early as 1763–1769), Derr had purchased several tracts of land from the William Penn family and other neighboring land owners, the largest of which was known as "The Prescott". Having been on the land for such a long time, Derr had befriended the local Native Americans of the area. His relationship with these indigenous peoples was so well founded that, even as many of the other local settlers' homesteads we routinely were sacked by Native Americans, Derr's lands remained free from attacks. Subsequently, in 1784, he worked with Samuel Weiser to lay out his combined land tracts, and create Derrstown. The name was later changed to Lewisburgh when Union County was separated from Snyder County.