Ten miles southeast of Walla Walla, the Blue Mountains rise abruptly from the rolling wheat fields of the Columbia Plateau. The uplifted basalt bedrock along the flanks of the Blue Mountains has been vigorously dissected by the tributaries of the Walla Walla River during their 5000 foot drop from the range crest to the plains below. The resulting topography is typified by steep-sided cliffy canyons separated by narrow ridges. The vegetation along the flanks alternates between grassy south-facing slopes and forested north-facing slopes. In contrast, the topography of the broad and generally heavily forested crest is rather subdued.

The steep topography along the flanks of the Blue Mountains forces most roads and trails to follow stream courses or ridge crests. Most routes connecting valleys with ridge crests are quite steep and make for rigorous climbing on a bicycle. However, once the crest of the range is reached by either a valley or ridge, the gentler topography permits a wider variety of routes.