The Battle of Grand Gulf was fought on April 29, 1863, during th: The next day, Union forces crossed the river at Bruinsburg, Mississippi.  A Union victory in the Battle of Port Gibson on May 1 secured the beachhead and forced the abandonment of the position at Grand Gulf, which became a Union supply point.  Grant's command moved inland, and after defeating Confederate forces in the Battle of Champion Hill on May 16, began the Siege of Vicksburg two days later.  Vicksburg surrendered on July 4, marking a major Confederate defeat and a turning point in the war. The Grand Gulf battlefield is preserved in Grand Gulf Military State Park, which was listed on the National Register of Historic Places in 1972.