The strength of the Union during the Battle of Arkansas Post on 9 January 1863 was severely overpowering to the Confederates. The Union had 33,000 men while the Confederacy only had 5,500. Needless to say, the Confederates were quite surprised at the number they were up against. The Union had a sweeping victory. It was one of the largest surrenders for the Confederates west of the Mississippi. Porter personally received the surrender from the Confederates on 11 January as he pressured them from the sea.