The Meramec River, sometimes spelled Maramec River, is one of the longest free-flowing waterways in the U.S. state of Missouri, draining 3,980 square miles (10,300 km2) while wandering 218 miles (351 km) from headwaters southeast of Salem to where it empties into the Mississippi River near St. Louis at Arnold and Oakville. 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. Genevieve, and Texas. Between its source and its mouth, it falls 1,025 feet (312 m). Year-round navigability begins above Maramec Spring, just south of St. James. 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.

Missouri is a landlocked state in the Midwestern region of the United States. Ranking 21st in land area, it borders Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas to the south and Oklahoma, Kansas, and Nebraska to the west. In the south are the Ozarks, a forested highland, providing timber, minerals, and recreation. The Missouri River, after which the state is named, flows through the center and into the Mississippi River, which makes up the eastern border. With over six million residents, it is the 18th-most populous state of the country. The largest urban areas are St. Louis, Kansas City, Springfield, and Columbia; the capital is Jefferson City.