Charlestown is a town in Sullivan County, New Hampshire, United States. The population was 5,114 at the 2010 census. The town is home to Hubbard State Forest and the headquarters of the Student Conservation Association.
The primary settlement in town, where 1,152 people resided at the 2010 census, is defined as the Charlestown census-designated place (CDP) and is located along New Hampshire Route 12. The town also includes the villages of North Charlestown, South Charlestown and Hemlock Center.
The area was first granted on 31 December 1735 by colonial governor Jonathan Belcher of Massachusetts as Plantation No. 4, the fourth in a line of forts on the Connecticut River border established as trading posts. Settled in 1740, Number Four was the northernmost township, and its 1744 log fort became a strategic military site throughout the French and Indian Wars. Several settlers were ambushed and captured by the Indians, and in 1747 the fort was besieged for three days by a force of 400 French and Indians. Captain Phineas Stevens and 31 soldiers, stationed at the fort, repelled the attack. Their success became well-known, and the fort was never attacked again.
On 2 July 1753, the town was regranted as Charlestown by Governor Benning Wentworth, after Admiral Charles Knowles of the Royal Navy, then governor of Jamaica. Admiral Knowles, in port at Boston during the 1747 siege, sent Captain Stevens a sword to acknowledge his valor. The town responded by naming itself in his honor. In 1781, Charlestown briefly joined Vermont because of dissatisfaction with treatment by the New Hampshire government. Returning at the insistence of George Washington, it was incorporated in 1783.
The community developed into a center for law and lawyers, second regionally only to Boston. Its prosperity would be expressed in fine architecture. Sixty-three buildings on Charlestown's Main Street are now listed on the National Register of Historic Places. They include the Gothic Revival South Parish Church erected by master-builder Stephen Hassam in 1842, St. Luke's Church designed by Richard Upjohn in 1863, and the Italianate Town Hall designed in 1872 by Edward Dow, New Hampshire's most prominent architect after the Civil War. Dow also designed Thompson Hall, centerpiece of the University of New Hampshire.
A reproduction of the Fort at Number 4 is now a historical site, where military reenactments and musters occur frequently throughout the summer months. Tours are offered of its stockaded parade ground and pioneer-style houses.