Collier Mountain is a ridge in the Ridge and Valley section of the Appalachian Mountains in Allegany County, Maryland. Rising to 1,457 feet, it stands about 5 miles southeast of Cumberland and extends roughly 6 miles northeast. The ridge begins near the North Branch Potomac River close to its confluence with Patterson Creek and continues to Murley Branch south of Breakneck Hill. As part of the folded terrain that defines this section of the Appalachians, it reflects the distinctive landscape of the region.