Defiance is a city in the northwestern part of the U.S. state of Ohio, in Defiance County, about 55 miles southwest of Toledo. The population was 16,465 at the 2000 census. It is the county seat of Defiance County. The city is on the site of Fort Defiance, built by General "Mad" Anthony Wayne in August 1794 at the confluence of the Auglaize and Maumee rivers. General Wayne surveyed the land and declared to General Scott, "I defy the English, Indians, and all the devils of hell to take it." This area became Fort Defiance. Today a lone pair of cannons outside the city library on the Maumee River overlook the confluence and mark the location of Fort Defiance, which faced the confluence.
Defiance is located at 41°16′55″N 84°21′46″W / 41.28194°N 84.36278°W / 41.28194; -84.36278 (41.281891, -84.362856).
According to the United States Census Bureau, the city has a total area of 11.0 square miles (28.6 km²), of which, 10.5 square miles (27.3 km²) of it is land and 0.5 square miles (1.3 km²) of it (4.44%) is water.