 The frontier county became an early crossroads, beginning with a California Gold Rush and developing into the Butterfield Overland Mail, Civil War trails and railroads such as the St. Louis and San Francisco Railway, the Little Rock and Fort Smith Railroad, and the St. Louis, Iron Mountain and Southern Railway.Today the county is home to the intersection of two major interstate highways, Interstate 40 (I-40) and I-49.Crawford County is part of the Fort Smith metropolitan area.