Grant decided to land troops on the Mississippi side of the river below Vicksburg in April. After pushing aside Confederate resistance at the battles of Port Gibson and Raymond, Grant's soldiers moved against Jackson, Mississippi, and captured the city from a Confederate army assembled to support Vicksburg. The Confederate defenders of Vicksburg had moved east from the city but were defeated at the Battle of Champion Hill on May 16. By May 18, Grant's men had reached Vicksburg. Frontal attacks against the city on May 19 and 22 failed will significant losses, and the city was placed under siege. The siege of Vicksburg continued until the Confederate defenders surrendered on July 4. After Vicksburg surrendered, the Confederate garrison of Port Hudson, Louisiana, followed suit, giving the Union full control of the Mississippi River.