Several Indian mounds built in Cary between 1200 and 1400 A.D. still stood there at the time of the Civil War. During the Steele's Bayou Expedition, flooding from the overflowing Mississippi and Yazoo Rivers made these mounds valuable high, dry ground for observing troop movements. After reaching the Federal fleet about five miles north on March 21, 1863, Union Colonel Giles Smith sent three companies of the 6th and 8th Missouri Infantry back to the mounds to guard the south flank of Federal forces on Deer Creek as they withdrew to Hill Plantation. The Steele's Bayou Expedition ended in dismal failure for Federal forces and nearly brought catastrophic results for Rear Admiral David D. Porter, whose fleet escaped capture or destruction only because Union infantry arrived in time. The failure of the Bayou Expeditions then compelled Major General Ulysses S. Grant to seek a more favorable route to capture Vicksburg.