Early in the American Civil War, the United States Navy decided that deep water coastal supply stations in Federal hands were spaced too far apart for blockading ships to operate effectively. Initially, a fleet was sent to capture Port Royal Sound (South Carolina) and that was completed on November 8, 1861.
The next objective was Fernandina, Florida, located twenty-five miles north of Jacksonville on the Atlantic coast. Fernandina was also the eastern terminus of the railroad that crossed Florida to Cedar Keys on the Gulf of Mexico. Near Fernandina was Fort Clinch, built but not completed before the war. Fort Clinch was in Confederate hands, so a significant Federal Navy force was sent south.