The northern region is part of the Columbia Plateau, where higher levels of rainfall allow the largest industry on private land to be the cultivation of alfalfa and hay.

About 16 million years ago, during the early Miocene epoch, lava flows from volcanic eruptions covered about half the surface area of Oregon.

The climate of the high desert provides habitat for mammals such as pronghorn, coyote, mule deer, black-tailed jackrabbit, and cougar.

The Blue Mountains are the geographical boundary to the north, marking the northern end of the high desert's semi-arid plateau.

The southern high desert is part of North America's Basin and Range Province, which extends south through Nevada and Arizona and into Mexico.

[15][16] Between 17 and 15 million years ago, magma from deep beneath eastern Oregon rose to the Earth's surface, causing a period of significant volcanic activity.

Eventually, these lava flows covered half the state of Oregon, creating a formation known as the Columbia River Basalt Group, the geologic foundation beneath much of the high desert.

The escarpment-type mountains and high-elevation valleys created by these faults produced the basin and range landscape that makes up much of Oregon's high desert country.

As each ice sheet melted, runoff and increased rainfall filled many of the region's closed basins, forming large pluvial lakes.

[citation needed] Annual precipitation throughout Oregon's high desert region is relatively low, averaging less than 15 inches (380 mm) per year in most areas.

[21][15][22] The majority of high desert areas receive most precipitation in the winter months, decreasing steadily through late summer into the fall.

Some areas in the eastern and southern parts of the region receive peak precipitation in the late spring and early summer.

[21][15] The Oregon Badlands Wilderness, 15 miles (24 km) east of Bend, has vegetation typical of the high desert region.

The area is dominated by big sagebrush and rabbitbrush along with hardy grasses like Idaho fescue, bluebunch wheatgrass, and bunchgrass.

In the spring, there are native wildflowers such as yellow Oregon sunshine, dwarf purple monkeyflower, sulfur buckwheat, Indian paintbrush, and mariposa lilies.

Other high desert wildflowers common throughout the region include buttercups, larkspur, phlox, primroses, and coral mallow.

[28][29] Throughout the high desert region, mule deer, pronghorn, coyotes, American badgers, and black-tailed jackrabbits are common.

This area is home to several species of arachnids, including the Northern scorpion, Western black widow, and the banded garden spider.

These Native Americans were once semi-nomadic hunter-gatherers who relied on nuts, roots, seeds, berries, eggs, and animals such as deer, pronghorn, geese, quail, rabbits, and bear,[36][37][38] following their food to high and low elevations depending on the time of year.

Made out of sagebrush, willow, tule plant, Indian hemp, and sumac fibers, the baskets are tight enough to carry water.

The settlers won the war and then set aside the Malheur Reservation for the Northern Paiute and other Oregon Native American tribes.

Thousands of these emigrants reached the area from the west, crossing the Cascade Range to make land claims in eastern Oregon.

[43] The high desert area was settled by Euro-Americans later than western Oregon was in part because of Elijah White's failure to find a pass east through the Cascades.

They were sent from Boise, Idaho, to build a military camp in the high desert, and they built it east of the Warner Lakes because they doubted that they could cross the series of wetlands.

The Bannock and the Northern Paiute suffered from violence during the conflict, and once the settlers had won the war, the natives were allotted to various reservations.

A 1996 National Geographic magazine "Map of the United States Physical Landscape" used the pioneer name, Great Sandy Desert, to identify the southeastern quarter of Oregon.