Steptoe Butte is a quartzite island jutting out of the
silty loess of the
Palouse hills in Whitman County, Washington. The rock that forms
the butte is over 400 million years old, in contrast with
the 15-7 million year old
Columbia River basalts that underlie the rest of the
Palouse (such "islands" of ancient rock have come to be
called buttes, a butte being defined as a small hill
with a flat top, whose width at the top does not exceed
its height).
A hotel built by Cashup Davis stood atop Steptoe Butte from 1888 to 1908, burning down several years after it closed. In 1946, Virgil McCroskey donated 120 acres (0.49 km2) of land to form Steptoe Butte State Park, which was later increased to over 150 acres (0.61 km2). Steptoe Butte is currently recognized as a National Natural Landmark because of its unique geological value. It is named in honor of Colonel Edward Steptoe.
