<Ul> <Li> Union blockade </Li> <Li> Eastern </Li> <Li> Western </Li> <Li> Lower Seaboard </Li> <Li> Trans - Mississippi </Li> <Li> Pacific Coast </Li> </Ul> <Li> Trans - Mississippi </Li> <P> The American Civil War was fought in the United States from 1861 to 1865 . The result of a long - standing controversy over slavery, war broke out in April 1861, when Confederates attacked Fort Sumter in South Carolina, shortly after President Abraham Lincoln was inaugurated . The nationalists of the Union proclaimed loyalty to the U.S. Constitution . They faced secessionists of the Confederate States of America, who advocated for states' rights to expand slavery . </P> <P> Among the 34 U.S. states in February 1861, seven Southern slave states individually declared their secession from the U.S. to form the Confederate States of America, or the South . The Confederacy grew to include eleven slave states . The Confederacy was never diplomatically recognized by the United States government, nor was it recognized by any foreign country (although Britain and France granted it belligerent status). The states that remained loyal, including the border states where slavery was legal, were known as the Union or the North . </P>

Who declared war to start the civil war