In April of 1861, the U.S. Navy formed a blockade of Confederate ports that lasted the duration of the war. When Union forces gained control of the Mississippi River, the western Confederacy was separated from its sisters in the east. The conveyance of mail between the divided territories became an extremely dangerous proposition. Trans-Mississippi blockade-run covers are often water stained because of the perilous journey they endured. Most often, they were carried across the river in half-sunken boats in the dead of night. The forty-cent rate such delivery commanded emphasizes the hazards involved for the mail carrier.