The Great Black Swamp was a glacially fed wetland in northwest Ohio and 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 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 farmland. However, this development has been detrimental to the ecosystem as a result of agricultural runoff. This runoff, in turn, has contributed to frequent toxic algal blooms in Lake Erie.
View from a ridge near Benton Ridge, Ohio, which demarks the edge of the former Great Black Swamp. The ridge was formed at the southern shore of the ancient lake. In the distance, a completely flat expanse of agricultural land extends to the horizon. In the foreground a ditch used to drain the swamp is visible.
A restored swamp section in Bowling Green, Ohio.
Northwest Ohio, or Northwestern Ohio, consists of multiple counties in the northwestern corner of the US state of Ohio. This area borders Lake Erie, Southeast Michigan, and northeastern Indiana. Some areas are also considered the Black Swamp area. The Toledo metropolitan area is part of the region.
Toledo is the region's principal and largest city
Bowling Green is Northwest Ohio's fourth largest city, and largest Toledo suburb
Downtown Lima, Ohio on a late March day
Defiance, Ohio is the seventh largest town in the region
