Alexandria Township is a township in Hunterdon County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 4,809,
Alexandria was formed by Royal charter on March 5, 1765, from portions of Bethlehem Township, and was incorporated as one of New Jersey's initial 104 townships by an act of the New Jersey Legislature on February 21, 1798. Portions of the township were taken to form Frenchtown (April 4, 1867), Holland Township (April 13, 1874, restored to Alexandria on March 4, 1878, and recreated on March 11, 1879) and Milford (April 15, 1911). The township was named for James Alexander, a surveyor who served as New Jersey Attorney General and who had acquired of land in the area in 1744. Pittstown is an unincorporated community that is also spread across Franklin Township and Union Township.
The township borders the municipalities of Bethlehem Township, Franklin Township, Frenchtown, Holland Township, Kingwood Township, Milford and Union Township in Hunterdon County; and both Bridgeton Township and Tinicum Township in Bucks County across the Delaware River border with the Commonwealth of Pennsylvania.