Book: US Civil War Artillery

Since the first line of defense of the United States was heavy artillery, more attention was logically paid to its development and improvement than the field. For example, in 1855, according to the Chief of the military leadership, this department purchased 54 ten-inch mortars and 68 five-inch ones. For comparison, in the same year, the same department purchased only 39 light bronze cannons and only two howitzers of various calibers to form field artillery. In general, the army installed 224 heavy coastal and garrison cannons, mainly along the coast of San Francisco, although many guns were sent to new regions. In the same year of 1855, the US Army ten-inch and eight-inch mortars fleet consisted of 2,319 units, as well as 2,957 units of heavy coastal artillery.
In January 1860, the coastal cities of America defended 61 fort. However, in many of them there were no garrisons - there was an acute shortage of soldiers in front of the army. Of all the forts along the south coast, which hit the first strike in 1861, only a few had garrison: Fort Taylor, Florida (52 people), Fort Sumter, South Carolina (89 people), Fort Pickens, Florida (59 people).
Quite often, the United States guns fell into the hands of the Confederates when seizing the incomplete forts by local rebels, especially in the southern regions. Thus, armament on both sides in a short period of time became approximately equal.