High Dyke is a minor road following a length of the Roman Road Ermine Street in the English county of Lincolnshire, between Woolsthorpe-by-Colsterworth and Ancaster, and onwards nearly to Bracebridge Heath. It is also the name of a small settlement on that road, south-east from Great Ponton, near to the mouth of Stoke Tunnel on the East Coast Main Line. High Dyke is also a name for the general area between Easton and Great Ponton. On the Ordnance Survey 1:25000 sheets it is spelled High Dike.
Recent rebuilding of the A1 road junction at Woolsthorpe-by-Colsterworth in 2008 has included construction of a grade-separated road crossing in place of the disused railway bridge that was part of the High Dyke branch, a mineral railway used to export iron ore between 1916 and 1973.
There is a roundabout adjacent to Prince William of Gloucester Barracks east of Grantham, but all other junctions are conventional grade-level crossroads or T junctions.