The 103rd Engineer Battalion is an engineer battalion of the United States Army, raised from the Pennsylvania Army National Guard. It is one of several current units with extensive Colonial era roots and campaign credit for the War of 1812. In 1775 when the Associated Regiment of Foot of Philadelphia was reorganized as the Associators of the City and Liberties of Philadelphia, it included one battalion of artillery. On 1 May 1775, this artillery battalion underwent further reorganization to form the Philadelphia Artillery Battalion under the command of Colonel Samuel Mifflin.