Fort Sumter fired on by Confederate batteries -- the conflict begins.
President Lincoln issued proclamation declaring blockade of Southern ports from South Carolina to Texas.
Norfolk Navy Yard partially destroyed to prevent Yard facilities from falling into Confederate hands and abandoned by Union forces.
Commander S. C. Rowan, U.S.S Pawnee , demanded the surrender of Alexandria, Virginia; an amphibious expedition departed Washington Navy Yard and occupied the town.
John LaMountain made first ascent in a balloon from Union ship Fanny at Hampton Roads to observe Confederate batteries on Sewell's Point, Virginia.
Union forces under Flag Officer S. H. Stringham and General B. F. Butler received the unconditional surrender of Confederate-held Forts Hatteras and Clark, closing Pamlico Sound.
Confederate naval forces, including CSS Curlew , Raleigh , and Junaluska , under Flag Officer W. F. Lynch, CSN, captured steamer Fanny (later CSS Fanny ) in Pamlico Sound with Union troops on board.
Naval forces under Flag Officer S. F. Du Pont captured Porr Royal Sound.
U S S Tyler , Commander H. Walke, and USS Lexington , Commander R. Stembel, supported 3,000 Union troops under General Grant at the Battle of Belmont, Missouri. and engaged Confederate batteries along the Mississippi River
USS San Jacinto , Captain C. Wilkes, stopped British mail steamer Trent in Old Bahama Channel and removed Confederate Commissioners James Mason and John Slidell.
Thaddeus Lowe made balloon observation of Confederate forces from Balloon-Boat G. W. Parke Curtis anchored in Potomac River.
Fingal (later CSS Atlanta ), purchased in England, entered Savannah laden with military supplies -- the first ship to run the blockade solely on Confederate government account.
Congress enacted legislation providing for the Medal of Honor.