Black Swamp
The Great Black Swamp (also known simply as the Black Swamp), was a glacially fed wetland in northwest Ohio and extreme northeast Indiana, United States, that existed from the end of the Wisconsin glaciation until the late 19th century. Comprising extensive swamps and marshes, with some higher, drier ground interspersed, it occupied what was formerly the southwestern part of proglacial Lake Maumee, a holocene precursor to Lake Erie. The area was about 25 miles (40 km) wide (north to south) and 100 miles (160 km) long, covering an estimated 1,500 square miles (4,000 km2). Gradually drained and settled in the second half of the 19th century, it is now highly productive farm land.
The land once covered by the swamp lies primarily within the Maumee River and Portage River watersheds in northwest Ohio and northeast Indiana. The boundary was determined primarily by ancient sandy beach ridges formed on the shores of Lakes Maumee and Whittlesey, after glacial retreat several thousand years ago. It stretched roughly from Fort Wayne, Indiana in the west, eastward to the Ottawa National Wildlife Refuge near Port Clinton along the Lake Erie shore, and from (roughly) US 6 south to Findlay and North Star, Ohio. Near its southern edge at the southwestern corner of present-day Auglaize County, the swamp was so impervious to travel that wheeled transportation was impossible during most of the year, and local residents thought the rigors of travel to be unsuitable for anyone except adult men.
...
Wikipedia