Thomas Sydenham Hardee (1832 - 1880) was a cartographer and civil engineer based in New Orleans who primarily produced maps of his home city. He appears to have produced military maps for the Confederacy during the Civil War before shifting focus to maps of New Orleans and its surroundings in peacetime. On an 1876 report on the waters of Lake Pontchartrain and the Bonnet Carré Spillway he is listed as the 'City Surveyor,' a position he appears to have held for several years.