The county is located on U.S. 78, about 16 miles northwest of Birmingham, in the north central part of Alabama. It is the 20th largest in size, containing 804 square miles. Elevation ranges from approximately 298 feet to 664 feet. The county is located within the Sand Mountain major land resource area. The land surface is highly dissected and contains narrow valleys and broad plateaus.
Water supplies are adequate for domestic uses in most areas.
There are several public water systems throughout the county, but many rural residents have dug wells as a source of water. Smith Dam, located on the Sipsey Fork of the Black Warrior River creates more than 8,000 acres of surface water for a habitat and recreation. Tributaries of the Black Warrior River provide drainage. Coal and timber are major resources of Walker County. The oak and pine forests include loblolly, longleaf, slash and shortleaf pines, red and white oak, sweetgum and yellow poplar.