Department of the Gulf

The Department of the Gulf was a command of the United States Army in the nineteenth and early twentieth centuries and of the Confederate States Army during the Civil War.

The department was constituted on February 23, 1862 when the United States War Department issued General Orders No. 20; the department consisted of "...all of the coast of the Gulf of Mexico west of Pensacola harbor, and so much of the Gulf States as may be occupied by the forces under Major General B.F. Butler." On March 20, 1862, Butler activated his command at Ship Island, Mississippi by issuing General Orders No. 1 (Department of the Gulf) assuming his new command.

United States Navy's West Gulf Blockading Squadron captured New Orleans, Louisiana on April 29, 1862, Butler moved his headquarters to New Orleans on 1 May. The department, sometimes referred to as the Army of the Gulf, became a union occupying force in the region.

The department, frequently referred to as the Gulf District, was established on July 2, 1862 as a part of Department No. 2; its area was defined as the coast from the Pearl River to the Apalachicola River northward to latitude 32° north. On November 3, 1863, the northern boundary was extended to latitude 33° north. On July 25, 1863, the department/district was transferred to the Department of Mississippi and Eastern Louisiana. It remained in that department only until January 28, 1864, when it was transferred to the Department of Alabama and Eastern Mississippi. Upon being transferred, the department/district boundaries were redefined as beginning at the mouth of the Pearl River, running north to latitude 32° north, east to the Georgia State line and south to the Gulf of Mexico. On May 8, 1864, the boundary was again modified to define the eastern edgbe as being the intersection of latitude 32° north with a line running from the junction of the Coosa and Tallapoosa to point where the Choctawhatchee River entered Florida then following the Choctawhatchee to its mouth on the Gulf of Mexico. The department/district surrendered on May 4, 1865.

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