The Mississippi River Squadron was the Union brown-water naval squadron that operated on the western rivers during the American Civil War. It was initially created as a part of the Union Army, although it was commanded by naval officers, and was then known as the Western Gunboat Flotilla and sometimes as the Mississippi Flotilla. It received its final designation when it was transferred to the Union Navy at the beginning of October 1862.

Charles Henry Davis was a self-educated American astronomer and rear admiral of the United States Navy. While working for the United States Coast Survey, he researched tides and currents, and located an uncharted shoal that had caused wrecks off of the coast of New York. During the American Civil War, he commanded the Western Gunboat Flotilla, where he won an important engagement in the First Battle of Memphis before capturing enemy supplies on a successful expedition up the Yazoo River. Davis was also one of the founders of the National Academy of Sciences in 1863 and he wrote several scientific books.