Washington Township is a township in Lycoming County, Pennsylvania, United States. The population was 1,613 at the 2000 census. It is part of the Williamsport, Pennsylvania Metropolitan Statistical Area.
Washington Township was formed as part of Northumberland County in 1786. It originally extended from White Deer Hole Creek north to the West Branch Susquehanna River with its eastern boundary also formed by the west branch. The western limit was ambiguous, but most historians assumed that the western boundary followed a line that extended to the south opposite the mouth of Pine Creek in what is now eastern Clinton County. Washington Township is older than Lycoming County. Therefore, it was one of the original townships in Lycoming County. Seven additional townships were created from land that was originally part of Washington Township. They are Armstrong, Bastress, Brady, Clinton, Limestone, Nippenose and Susquehanna Townships. The township is named for the hero of the American Revolution and the 1st President of the United States, George Washington.