1. On July 11, 1805, Meriwether Lewis and William Clark's Corps of Discovery expedition reached what is now known as Celilo Falls on the Columbia River. The falls were an important fishing site for Native American tribes and were later submerged by the construction of The Dalles Dam.

2. The Oregon Territory was established on July 11, 1848, through the signing of the Oregon Treaty between the United States and Great Britain. This established the border between Canada and the United States along the 49th parallel.

3. On July 11, 1911, the Pendleton Round-Up became the first rodeo to be incorporated as a non-profit organization in the United States. The annual event, held in Pendleton, Oregon, continues to attract thousands of visitors each year.

4. The Tillamook Burn, a massive wildfire that burned over 300,000 acres of forested land in Oregon, was first reported on July 11, 1933. The fire caused significant damage to logging operations and wildlife habitats, but also led to major innovations in reforestation and forest management.

5. July 11, 1971, marked the first official day of operation for the TriMet public transit system in the Portland metropolitan area. Today, TriMet operates buses, light rail trains, and commuter trains, serving millions of riders each year.