The A1101 is the lowest road in Great Britain; along its 53 miles (85 km) approx. stretch it rarely rises above sea level. The road runs from Bury St. Edmunds north west to Littleport where it disappears for approximately 2 miles (3.2 km), 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 famously low-lying area to Suffolk through Cambridgeshire. It is the main road for access between Lincolnshire and the Fenlands. The stretch between Wisbech and Long Sutton was previously designated the A150.
The road passes through: Long Sutton, Tydd St Mary, Tydd Gote, Four Gotes, Wisbech, Outwell, Upwell, Lakesend, Welney, Littleport (bypass), Kennyhill, Beck Row, Mildenhall, Icklingham, Lackford, Flempton, Hengrave, Fornham All Saints and Bury St Edmunds. From Outwell north, where the western terminus of the A1122 is at, the road is classified as a primary route. At Welney, the road often floods, causing it to be closed for 70 days in 2007. The Environment Agency said that "The A1101 road is on a causeway across the flood area and was expected to be under water at times."
It crosses the following major roads (from N to S):A17 - Newark-on-Trent to King's Lynn
A47 - Great Yarmouth to Birmingham (partially reclassified as the B4114)
A10 (Great Cambridge Road) - London Bridge to King's Lynn
A11 - London to Norwich
A14 - Port of Felixstowe to the M1 junction with the M6 (19) NE of Rugby.