The Lava Plains ecoregion is immediately south of the Columbia Plateau ecoregion, west of the Cascades Foothills ecoregion and east of the Blue Mountains ecoregion.

It contains dissected lava plains, rolling hills, alluvial fans, valleys, and scattered mountain ranges in the northern part of the Great Basin. Although arid, the ecoregion is higher and cooler than the Snake River Plain to the north and has more available moisture and a cooler climate than the Central Basin to the south.

The western part of the region is internally drained; its eastern stream network drains to the Snake River system.

Crooked River Gorge

Inland Desert Route