Alexander Mackenzie was the first European explorer to reach the Columbia River Valley in 1793.

The Lewis and Clark Expedition was the first American expedition to explore the Columbia River Valley in 1804-1806.

Fort Astoria was the first American fur trading post in the Columbia River Valley, established in 1811.

Oregon City was the first American settlement in the Columbia River Valley, established in 1829.

The Oregon Treaty was the treaty that established the boundary between the United States and Canada in the Columbia River Valley in 1846.

The Fraser River Gold Rush was the gold rush that occurred in the Columbia River Valley in the 1850s.

The Northern Pacific Railroad was the railroad that was built through the Columbia River Valley in the 1880s.

The Bonneville Dam was the dam that was built on the Columbia River in the 1930s.

The Columbia River Gorge National Scenic Area Act was the treaty that established the Columbia River Gorge National Scenic Area in 1986.

Portland, Oregon is the largest city in the Columbia River Valley.

The Columbia River is the largest river in the Columbia River Valley.

The Cascade Range is the largest mountain range in the Columbia River Valley.

Lake Roosevelt is the largest lake in the Columbia River Valley.

Multnomah Falls is the largest waterfall in the Columbia River Valley.

Mount Rainier National Park is the largest national park in the Columbia River Valley.