The main purpose of the Union's naval blockade during the Civil War was to diminish the Southern economy by preventing the export of cotton and the import of essential supplies and goods.

Instituted by President Abraham Lincoln in 1861, this strategy aimed to cripple the Confederacy's ability to sustain its war efforts and cut off resources necessary for military operations. The blockade significantly hindered Southern trade and created shortages, ultimately contributing to the Union's victory by weakening Confederate resolve and capability.