This map of the county of Leicestershire is the first of the county at the scale of one inch to the mile and is here offered in its FIRST STATE. It is one of the rarer of the eighteenth century surveys and is notable for the fact that unlike his major experienced competitors in this field, John Rocque and Thomas Jefferys, John Prior was a teacher, clergyman and mathematician. Despite this apparent lack of capability, he was awarded the Silver Medal by the Society of Arts and 20 guineas. The survey itself was undertaken by Joseph Whyman from 1775-77 and lower right on the map we find, rather unusually, a complete triangulation of the county showing how the work progressed. It was published by Prior in 1779.

On the map the parallel and meridian of Leicester are shown with the boundaries of the hundreds coloured. Turnpike roads have their Tollbars and Milestones identified. An indication of the importance of industry to this county is shown by the identification of Coal Pits, Lime Works, Wind Mills and Water Mills. The inset lower left is a detailed plan of the city of Leicester which was criticised for inaccuracies. Indeed, it was excused for a lack of time to survey it properly. The whole map is engraved by John Luffman who completes it with a beautiful cartouche including both title and dedication to the Earl of Huntingdon. The apparent bucolic depiction in fact appears to bear a quantity of coal in front. Further editions were published in 1804 and 1819 and all are rare. Baum (1972) pp. 37-9; Deadman & Brooks (2010) p. 100; Harley (1965) pp. 56 & 63; Rodger (1972) no. 262.