You're probably right Billy. There are 2 hand written dates of 1854 on the right hand side and bottom borders of the map. The reason I thought it was late 40's, it looks like they were doing a census every 10 years, and this map didn't have an 1851 census on it.
There is an interesting date and note on he top left hand border which is, '1868, Sept, 12. Gift of President Felton's Family'.