The Geography of Atlanta encompasses 132.4 square miles (342.9 km2), of which 131.7 square miles (341.1 km2) is land and 0.7 square miles (1.8 km2) is water. The city is situated among the foothills of the Appalachian Mountains, and at 1,050 feet (320 m) above mean sea level, Atlanta has the highest elevation among major cities east of the Mississippi River. Atlanta straddles the Eastern Continental Divide, such that rainwater that falls on the south and east side of the divide flows into the Atlantic Ocean, while rainwater on the north and west side of the divide flows into the Gulf of Mexico. Atlanta sits atop a ridge south of the Chattahoochee River, which is part of the ACF River Basin. Located at the far northwestern edge of the city, much of the river's natural habitat is preserved,