Geography of Oregon

Western Oregon's mountainous regions, home to three of the most prominent mountain peaks of the United States including Mount Hood, were formed by the volcanic activity of the Juan de Fuca Plate, a tectonic plate that poses a continued threat of volcanic activity and earthquakes in the region.

[8] The Columbia River, which forms much of Oregon's northern border, also played a major role in the region's geological evolution, as well as its economic and cultural development.

Plentiful salmon made parts of the river, such as Celilo Falls, hubs of economic activity for thousands of years.

Today, Oregon's landscape varies from rain forest in the Coast Range to barren desert in the southeast, which still meets the technical definition of a frontier.

Central Oregon's geographical features range from high desert and volcanic rock formations resulting from lava beds.

[23] The state's western region (west of the Cascade Range) has an oceanic climate, populated by dense evergreen mixed forests.

[24] The state's southwestern portion, particularly the Rogue Valley, has a Mediterranean climate with drier and sunnier winters and hotter summers, similar to Northern California.

[26] The eastern two thirds of Oregon, which largely comprise high desert, have cold, snowy winters and very dry summers.

Much of the east is semiarid to arid like the rest of the Great Basin, though the Blue Mountains are wet enough to support extensive forests.

[46] Astoria, at the mouth of the Columbia River, was the first permanent English-speaking settlement west of the Rockies in what is now the United States.