It was at the time of its downgrade a 1.3 miles (2.1 km) long dual carriageway, meeting the M6 at Junction 35.

Originally built in 1960 as the northern terminus of the M6 on the A6, the A601(M) became a spur to the M6 in 1970 when the mainline of the motorway was extended north.

Plans existed to extend this as part of an Arnside link road, which would have connected the Furness Peninsula with the M6, but they were scrapped for environmental reasons.

[4] In 1987, a link was constructed with the B6254, to remove traffic for Over Kellet Quarries and Kirkby Lonsdale passing through Carnforth.

[6] In late 2021, Lancashire County Council issued a revocation scheme for the remaining portion of the motorway to be downgraded to non-motorway status.