 Henshall worked with Brindley and John Smeaton in 1758 to survey the proposed Trent and Mersey Canal.In 1765 he helped survey the River Weaver from Winsford to Lowton, and in the same year planned a link from Cheshire to the Bridgewater Canal, and surveyed the River Severn.In 1768 Brindley, assisted by Henshall, surveyed the route of the Staffordshire and Worcestershire Canal.