Tamastslikt Cultural Institute is the strongest museum in the Pendleton area. Its exhibits tell the story of the Cayuse, Umatilla, and Walla Walla people, including the Oregon Trail and settlement history from the side usually treated as an afterthought in pioneer museums.
It is a short drive east of town near Wildhorse. Pair it with the downtown sights if you want Pendleton to feel like more than rodeo nostalgia.