On the morning of March 21, Major General O.O. Howard's Fifteenth and Seventeenth Corps faced the Confederate divisions of Major General Robert F. Hoke and Major General Lafayette McLaws west of Sam Howell Branch as a heavy drizzle fell. Major General Francis P. Blair, Jr.'s Seventeenth Corps strengthened its position on the eastern side of the branch, separated from the Confederate line by 300 yards of swampy land, a small ravine, and manmade obstructions. Under orders from Major General William T. Sherman to avoid a general battle, Howard held Blair back from attacking until 1:30 p.m., after learning that Major General Joseph Mower's division had attacked the Confederate left near Bentonville. Mower's First Division of the Seventeenth Corps had broken camp around 10:00 a.m. and been ordered to entrench on the right of Howard's line overlooking Sam Howell Branch to protect a ford, but before moving into position Mower secured Blair's permission to make a little reconnaissance of Confederate positions near Bentonville and, using a nearly impassable route toward Mill Creek, reached the weakly defended Confederate left flank by noon. To relieve pressure on Mower, Howard then ordered Blair and parts of Major General John A. Logan's Fifteenth Corps to advance across Sam Howell Branch against the Confederate lines. Fierce fighting followed, with Confederate trenches changing hands multiple times and heavy casualties on both sides. Although outnumbered and fearing that Mower's advance might cut off their only route of retreat, the Confederates held their positions along Sam Howell Branch until the battle ended.