Built in 1810 on Main Street in Middletown for the merchant Samuel Mather, the Federal-style General Mansfield House was later home to Mather’s daughter Louisa and her husband, General Joseph K. F. Mansfield. At the start of the Civil War, Mansfield was in charge of the defense of Washington, D.C. On September 17, 1862, he was killed at the Battle of Antietam (or Sharpsburg) in Maryland, haven just taken command two days before of the XII Corps of the Army of the Potomac. A monument and a mortuary cannon are dedicated to him on the battlefield of Antietam. There is also a monument in Middletown’s Indian Hill Cemetery, where he is buried. His house was later occupied by his descendants. Slated for demolition in the 1950s, it was saved by the Middlesex County Historical Society and now serves as the Society’s headquarters and museum.