The topography of Monument is defined by its valley setting. The city itself rests at an elevation of roughly 2,001 feet (610 meters) on the relatively flat floodplains of the North Fork John Day River.
Immediately surrounding the town limits, the terrain rises steeply into rolling hills, basalt canyons, and rugged plateaus. The lowest points in the area are found along the riverbed, while the highest points are the peaks of the nearby Blue Mountains and the distinctive rock formations—including the town's namesake "monument" rock—that punctuate the skyline.