The Meramec watershed covers six Missouri Ozark Highland counties—Dent, Phelps, Crawford, Franklin, Jefferson, and St. Louis—and portions of eight others—Maries, Gasconade, Iron, Washington, Reynolds, St. Francois, Ste.

The Meramec's size increases at the confluence of the Dry Fork, and its navigability continues until the river enters the Mississippi at Arnold, Missouri.

Early on, the river became an important industrial shipping route, with lead, iron, and timber being sent downstream by flatboat and shallow-draft steamboat.

Red Ribbon trout streams are managed by the Missouri Department of Conservation to produce trophy-sized fish.

Maramec Spring Park, south of St. James, is the home of an historic iron works and trout fishery.

World War II intervened, and plans were delayed and altered, but the Meramec Basin Project finally started moving forward in the 1960s.

At the request of Senators Jack Danforth and Tom Eagleton, Missouri Governor Kit Bond allowed a non-binding referendum to be put on ballots in twelve surrounding counties.

This was one of the first times that a Corps of Engineers project was stopped once construction had begun, and it marked a major victory for the American environmental movement.