I have been following this thread with interest, because in my hobby 'postal history' the mileage has always been important. We have a page on our website about it, which could be of interest because of the illustration of a page from John Cary's survey of the roads for the Post Office in 1802.. http://www.home.gil.com.au/~ears/mmintro.html an extract from the early postage rates shows : By Proclamation Charles 1 31 July 1635 within England, Wales and Scotland not exceeding 80 miles 2d for single letter exceeding 80 miles not exceeding 140 4d and exceeding 140 miles 6d. Then from 1812 ro 1840 (before the introduction of the Penny Post) the rates were charged over graduated scales from 'not exceeding 15 miles' to '700 miles and over' in 14 graduated stages, so the mileage was very important to the Post Office, and as Frank has said it was probably dependent on the reason the mileage was being measured. Eunice in Queensland