As part of their service to motorists, auto clubs, tire and oil manufacturers and later the federal government distributed guide books and maps for some of the nation’s roads. The highly illustrated cover of this guide highlights two of the National Road’s early twentieth century identities – as a federally numbered highway (US 40) and as the eastern-most segment of the National Old Trails Road, a consolidation of several highways to form a trans-continental route from Washington and Baltimore to California, promoted by the private National Old Trails Road Association. The cover also emphasizes the progress believed to have been made since the settlement of the nation.