Due to its unique topography, this site was designated a National Natural Landmark in 1968 by the National Park Service.  This 624-acre site protects the best remaining example of the unusual "mima mound" landscape.  Many hypotheses have been proposed, but there is no widely accepted explanation for the origin of the mysterious, regularly spaced six to eight foot tall mounds.  The site supports a native grassland ecosystem (referred to as "Puget prairie") and white topped aster, a state Sensitive plant species which occurs only within grasslands of the Puget Trough.  Visitor facilities include a 1/2 mile paved interpretive trail, an interpretive shelter with displays, a two mile loop trail, parking lot and restroom.  (Thurston County)

14th Annual Prairie Appreciation Day

May 9, 2009
10 a.m. to 3 p.m.

Glacial Heritage Preserve in Thurston County
Bring a picnic and explore 15 activity stations. No pets.
For more information, see event flyer.