The B1145 runs for about 52 miles (84 km) through the county of Norfolk, England, between King's Lynn and Mundesley.

This map, the first large-scale map (at one inch to the mile) of the whole county, is a record of the landscape and transport system of the county of Norfolk in late 18th century and shows that despite the parliamentary enclosure of the early 19th century the route has changed very little.

Much of the route on the map is highlighted in a pale pink, which marks it out as an important artery of the time.

[5] The route is dissected by several Roman roads, including the Peddars Way in the North West of Norfolk.

Road schemes at Bawdeswell, Aylsham and North Walsham have created interruptions to the original route, although the vast majority of it remains intact.