Geologic map and profiles of the north wall of the Snake River Canyon, Jerome, Filer, Twin Falls, and Kimberly quadrangles, Idaho

The Snake River Plain is a broad, arcuate region of low relief that extends more than 300 mi across southern Idaho.  The Snake River enters the plain near Idaho Falls and flows westward along the southern margin of the eastern Snake River Plain (fig. 1), a position mainly determined by the basaltic lava flows that erupted near the axis of the plain.  The highly productive Snake River Plain aquifer north of the Snake River underlies most of the eastern plain.