 The road runs from Bury St. Edmunds north west to Littleport where it disappears for approximately , it then re-appears on the other side of the A10 heading north through Wisbech and to its end at the A17 in Long Sutton.The A1101's route takes it across the Fens in Lincolnshire and Norfolk, a low-lying area to Suffolk through Cambridgeshire.It is the main road for access between Lincolnshire and the Fenlands.