What was the first armed conflict of the US Civil War?

Answer 1

There could be a number of answers, since there was never a formal declaration of war.

Congress did not recognise the Confederacy, so the Union was merely putting down a rebellion of some of its own states, not attacking an enemy nation.

The assault on Fort Sumter in April 1861 caused Lincoln to issue a call for volunteer troops, and this was taken as the nearest thing to a declaration of war. (Four states joined the Confederacy in response to it.)

There were then a few small skirmishes, but nothing substantial till July, when a Union army under McDowell marched out of Washington, expecting to take Richmond in a few days.

They were repulsed at Manassas/Bull Run, and this is normally regarded as the first battle.

Others have cited Fort Sumter itself, if not John Brown's rebellion or even the earlier Bleeding Kansas disturbances, as the first shots of the Civil War.

Answer 2

The bombardment of Fort Sumter and its surrender to Confederate forces led up to the unfolding of the US Civil War. It was not until President Lincoln called for 75,000 volunteers to end the Southern rebellion did the actual war take shape. And, it was that call up for Union volunteers that set off what would become the real war. In July of 1861, the first battle of major consequence was the First Battle of Bull Run.