On October 7, Buell's army, in pursuit of Bragg, converged on the small crossroads town of Perryville in three columns. Union forces first skirmished with Confederate cavalry on the Springfield Pike before the fighting became more general, on Peters Hill, when the Confederate infantry arrived. Both sides were desperate to get access to fresh water. The next day, at dawn, fighting began again around Peters Hill as a Union division advanced up the pike, halting just before the Confederate line. After noon, a Confederate division struck the Union left flank—the I Corps of Maj. Gen. Alexander M. McCook—and forced it to fall back. When more Confederate divisions joined the fray, the Union line made a stubborn stand, counterattacked, but finally fell back with some units routed.