From Washington To You

From Washington to you

Steptoe Butte

Steptoe Butte · Whitman County · state park dedicated July 4, 1946

A 3,612-foot Palouse quartzite island that gave geology the word “steptoe,” and that still holds some of the last Palouse prairie in Washington.

Washington DNR says Steptoe Butte is the origin of the geologic term “steptoe”: an isolated hill of older rock surrounded by a lava flow. The 3,612-foot quartzite butte is a National Natural Landmark for ecology and geology. DNR established a 437-acre Natural Area Preserve around it in 2018 to protect the largest known remaining Palouse prairie in Washington. DNR estimates only about 2 percent of that prairie’s historic range is left, and calls the ecosystem one of the most endangered in the continental United States.

The preserve is a key site for federally threatened Spalding’s catchfly. DNR also lists three other rare plants, four priority plant associations, and the Giant Palouse earthworm. State Parks says Columbia River basalt covered all but the highest quartzite peaks, and that later Ice Age flood silt and wind-blown loess built the Palouse soils. Parks dedicated the state park on July 4, 1946, and records the Indigenous names Se-empteeta or E-omoshtoss.

This pin is the butte summit. The sources below are Washington DNR and Washington State Parks pages.

  • Geography & Geology
  • Wildlife & Ecology
  • Indigenous History & Place

Sources (3)

Last reviewed: September 21, 2026

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