A 38.0 acre marine, freshwater, and terrestrial conservancy located on the eastern shoreline of Vashon Island at the end of 266th Lane overlooking Quartermaster Harbor.  The lake was formed after a massive ancient landslide created a rift along the west shore of Quartermaster Harbor. Over time, water trapped inside became Lost Lake. The site is owned by the Vashon Park District and managed by the Vashon Maury Island Land Trust.  The property conserves a sizable wetland or marsh and surrounding woodlands providing habitat for bald eagles, coopers hawks, red-tailed hawks, great horned owls and herons. The shoreline is valued for its eelgrass beds and spawning beds for surf smelt and pacific herring. It is a site for geoducks and other marine species.  Land Trust volunteers monitor and steward the property.

Island equestrian groups and individuals have developed and maintained an “informal” system of low-impact horse and walking trails across adjacent private properties to provide access around and through the site.  The community uses the upland as a continuation of a cross-island horse trail, as a hiking trail, and an education site.  The property can be accessed by boat and is used by boaters from Olympia to dig geoducks.