Fort Cascades served as the main post comprising several blockhouses set up to defend the vitally important transportation corridor along the Columbia River through one of the treacherous points along the river.

The Oregon Trail was a long and perilous route.  Perhaps the most difficult section lay almost at the trail’s end as it made its way through the Cascade Mountains to the promised lands of the Willamette Valley.  Once the Trail dropped down out of the Blue Mountains of northeastern Oregon, it followed along the Columbia River.  It was possible to float your wagons down much of the river, but most kept to the road leading up and down along the south side of the Columbia.  Crossing the John Day and Deschutes rivers were minor difficulties compared to the last difficulty lying ahead in the mountains.