Established in 1861, it operated on the Mississippi River and its tributaries, playing a crucial role in various military campaigns. The squadron was known as the "Brown-water navy" due to the muddy waters of the river, contrasting with the blue waters of the ocean. Under the command of Admiral David D. Porter from 1862, it supported ground forces and was instrumental in key battles, including those at Fort Henry and Fort Donelson, helping to secure Union control over the Mississippi River, which was vital for logistics and troop movements.