Castle Rock, Colo. 1/75, manuscript postmark on cover to Cincinnati, O., franked with manuscript canceled 3¢ Banknote, with original enclosure with some interesting content including K.P.R.R. (Kansas Pacific Railroad) blockade; minor cover soiling, otherwise Very Fine, the only confirmed territorial postmark from this town. Estimate  $200 - 300. The railroad attempted to establish its own town (New Memphis) about a mile from an existing settlement. The attempt failed and the post office was moved and re-named Castle Rock. $0 (Image)