The Lewis and Clark Expedition came down the Snake River to the present day site of Sacajawea State Park near Pasco in the fall of 1805. The Horse Heaven Hills are noted in their journal entry on October 16 as "a range of high Countrey which runs from S. W & N E and is on the opposit Side about 2 miles distant from the Columbia". In the following days, the expedition continued down the Columbia River as it goes around the Horse Heaven Hills through Wallula Gap.
