Mechanicsburg is a borough in Cumberland County, Pennsylvania, USA, eight miles (13 km) west of Harrisburg. It is part of the Harrisburg–Carlisle Metropolitan Statistical Area. Mechanicsburg was settled in 1806 and incorporated as a borough on April 12, 1828. It is in a rich agricultural region known as the Cumberland Valley, a broad zone between South Mountain and the ridge-and-valley Appalachians. In 1900, 3,841 people lived here; in 1910, 4,469, which increased to 5,709 in 1940. As of the 2010 census, the borough population was 8,981. Mechanicsburg is home of Jubilee Day, the largest and longest-running one-day street fair on the east coast. It is estimated as many as 60,000 people attend Jubilee Day annually. Mechanicsburg lies in the center of a regional transportation crossroads, with Interstate 81, Interstate 76, Interstate 83, US Route 11, and US Route 15 passing in close proximity to the borough.