01/04/1861 — Alabama militia sieze the U.S. arsenal at Mt. Vernon, AL. Alabama has not yet seceded.
01/05/1861 — Alabama militia sieze Ft. Morgan and Ft. Gaines in Mobile Bay.
01/07/1861 — Florida militia sieze the Federal fort at St. Augustine. Florida has not yet seceded.
01/08/1861 — Florida militia attempting to sieze Ft. Barrancas are driven off by Federal troops.
01/09/1861 — South Carolina militia fire on US merchant vessel Star of the West, preventing reinforcement and resupply of Ft. Sumter garrison.
Mississippi secedes.
01/10/1861 — Louisiana militia sieze all Federal forts and arsenals in the state. Louisiana has not yet seceded.
Florida (belatedly) secedes. Federal troops abandon Ft. Barrancas.
North Carolina militia capture Ft. Johnson and Ft. Caswell. North Carolina has not yet seceded.
01/11/1861 — Alabama (belatedly) secedes.
01/12/1861 — Florida militia demands the surrender of Federal troops in Ft. Pickens. The demand is refused.
Mississippi fortifies Vicksburg and closes the Mississippi River to all traffic. Mississippi is the only state on the river, at this point, which has seceded.
01/19/1861 — Georgia secedes.
01/21/1861 — Mississippi militia sieze Ft. Massachussetts and Ship Island.
01/25/1861 — Georgia militia sieze the federal arsenal at Augusta. North Carolina calls for a referendum on secession.
01/26/1861 — Georgia militia sieze Ft. Jackson and Oglethorpe Barracks.
Louisiana (belatedly) secedes.
01/31/1861 — The U.S. Mint in New Orleans is siezed by Louisiana militia.
02/09/1861 — Tennessee rejects secession in popular referendum by a large margin.
02/16/1861 — Texas militia sieze the federal arsenal at San Antonio. Texas has not yet seceded.
02/18/1861 — Texas militia besiege Federal army headquarters for Texas in San Antonio and force the surrender of over 3,000 troops. Texas has -still- not seceded.
Jefferson Davis inaugurated as President of the Confederacy.
02/21/1861 — The Confederate Provisional Congress orders Mississippi to end the blockade at Vicksburg.
02/23/1861 — Texas voters approve secession by a 75% majority, secession to take effect March 2 (Texas Independence Day).
02/28/1861 — North Carolina voters narrowly reject secession (by fewer than 1,000 votes).
03/01/1861 — Texas submits an article of secession to popular referendum for February 23.
03/02/1861 — Texas’s secession takes effect; that same day, Texas is admitted into the Confederacy.
03/03/1861 — The militia units in Charleston Harbor are taken under Confederate authority.
03/04/1861 — Lincoln inaugurated.
and your point?
Dozens upon dozens of forts across the south were revolutionary era structures built by the states or colonies. Others were built before the states in which they existed were acquired by the United States itself. In many cases this included the primary defensive fort for major harbors and inlets.
None of these various operations resulted in the loss of life due to the fact that these facilities were not defended, and the officials at each either resigned their employment, or in the case of military personnel, they returned north by boat or train.
Many of the properties were simply abandoned as the union army consolidated its troops from outlying posts.
Others were claimed by the states themselves for the simple reason that they had rightful ownership of the properties. Several of the coastal forts in the south dated back to the revolution and were built and paid for by the individual states, not the federal government, which acted only as conditional tenants to garrison them in defense.