Grant's Canal (also known as Williams's Canal) was an incomplete military effort to construct a canal through in Louisiana, across the Mississippi River from Vicksburg, Mississippi. During the American Civil War, United States Navy forces attempted to capture the Confederate-held city of Vicksburg in 1862, but were unable to do so with army support. Union Brigadier General Thomas Williams was sent to De Soto Point with 3,200 men to dig a canal capable of bypassing the strong defenses around Vicksburg. Despite help from local plantation slaves, disease and falling river levels prevented Williams from successfully constructing the canal, and the project was abandoned until January 1863, when Union Major General Ulysses S. Grant took an interest in the project.