The B677 was a short link road to the south of Grantham town centre.
It started on the A607 Harlaxton Road and headed east along Springfield Road. After a few bends and a bridge under the railway line the road ended after less than a mile on the A1 (now B1174) London Road, at its junction with the A152 (now A52).
Owing to the short length of the road it is not certain how long it lasted, although the number does appear on maps in the 1950s. The road certainly had Class II status in the 1990s, long after the construction of the A1 western bypass possibly put the road out of zone. What is certain is that the road is now a spur of the A607.