How long did union troops occupy the south?

Union troops occupied parts of the South during and after the Civil War, primarily from 1861 until 1877. The most intense occupation occurred during the war itself and continued during the Reconstruction era, which lasted from 1865 to 1877. Federal military presence aimed to enforce new laws and protect the rights of newly freed slaves, but by 1877, the last federal troops were withdrawn as part of a compromise that effectively ended Reconstruction.