Adventures in Mapland: Mima Mounds

One of the world's great geological mysteries, Mima Mounds are scattered throughout central Thurston County. There are about 30 different theories as to their origin, but no one knows for sure what caused these unique geological formations. About eight feet high and 30 feet across, the Mima Mound prairies host rare wildflowers, birds, and butterflies that only use this habitat.

Protecting 625 acres of native prairie, the Mima Mounds Natural Area Preserve is located just west of Littlerock (see Thurston County Map). 97% of Washington's native prairies have been converted into farmland, and native prairies like the Mima Mounds are threatened by non-native plants. Scott's broom poses a serious threat.

Stop at the kiosk near the parking area and climb the stairway to get a bird's eye view of the mounded prairie, then hike the nature trails that wind through the mounds. See the Thurston County Map to locate other mound areas in the county. The two most visible are located near Tenino.

At the south end of the Littlerock mounds, Bordeau Ranch is a one of Washington's most unique housing developments. Note the mounds that have been preserved as part of someone's front yard. Have you ever mowed a Mima Mound?