Williamsport is a city in and the county seat of Lycoming County, Pennsylvania in the United States. The population was 30,706 at the 2000 census. It is the principal city of the Williamsport, Pennsylvania Metropolitan Statistical Area, which is included in the Williamsport-Lock Haven, Pennsylvania Combined Statistical Area.Williamsport is known internationally as the birthplace of Little League Baseball. Neighboring South Williamsport is the headquarters of Little League Baseball and annually hosts the Little League World Series in late summer.