Some Postal documents 
This is a partial piece of the page from the National Archives of the Postal Ledger book written by hand of each Postmaster appointment for the County of Sullian, State of Pennsylvania. The listing at the bottom is for John Campbell of Campbellville 1851. Followed by the listing for his son Hiram Campbell. Note- Eagles Mere P.O was established in 1848, Millview in 1850 and Cherry Mills in 1850.
A Postcard from Mattie Bedford of the highly respected Bedford Clan, early pioneers of Campbellville. The postcard is  postmarked "Campbellville, PA. Sep. 1915". The postage stamp is 1 cent. The card was mailed at the Campbellville Post Office at the General Store at Campbellville.
A Postal form from the Post Office Department, Topographers Office, Washington dated Oct. 16th, 1882 sent to William Fawcett, U S Postmaster, Campbellsville, Sullivan County, Pa. The questionare asks for where it is situated in Forks Township. The name of the most prominent river and creek(s) nearby and their location to the post office. Its nearest Railroad station and name of the Railroad. The names of all other Offices near Campbellsville in different directions and their distance from it by the most direct roads. 
A section of a large Survey Map of all the Post Offices in Sullivan County, Pa. drafted by Richard Bedford, Campbellsville P.O., dated Oct. 30, 1880. This portion shows Campbellsville PO, the pond and Grist mill, the School house, Lick Creek and Level Branch and the adjoining Post Offices and the Postal Routes to each Office. The large river in the lower section of the map is the Big Loyalsock Creek.