Starting from Bodmin, the road runs past Liskeard, Saltash, Plymouth and Buckfastleigh to Exeter, then reemerges from its junction with the M5 motorway, ten miles north of Exeter, and heads north via Wellington, Taunton, Bridgwater, Bristol, Gloucester, Tewkesbury, Worcester, Bromsgrove, Birmingham, then bypasses Sutton Coldfield, Lichfield, Burton-upon-Trent and Derby before heading through Alfreton to end in Mansfield.
South of Birmingham, the road is paralleled by the M5 motorway.
