Millersylvania

Millersylvania State Park is a 842-acre forested sanctuary located in Thurston County, approximately 10 miles south of Olympia. The park centers around Deep Lake, a 75-acre glacial lake surrounded by old-growth forest featuring massive Douglas-firs and western red cedars. Named after early settler John Miller, a Civil War general who homesteaded the area in the 1850s, the park preserves some of the finest remaining lowland old-growth forest in western Washington. The park offers camping, swimming, hiking, and peaceful immersion in an ancient forest ecosystem just minutes from urban areas.

Millersylvania State Park's wildlife reflects its location in lowland Puget Sound forests surrounding a productive freshwater lake. Black-tailed deer are frequently observed throughout the park. Black bears occasionally visit from surrounding forest lands. The old-growth forest provides habitat for pileated woodpeckers, barred owls, and northern spotted owls. Numerous songbirds inhabit the multi-layered canopy including Pacific wrens, varied thrushes, and winter wrens. Deep Lake supports populations of trout, bass, and sunfish that attract bald eagles, osprey, and great blue herons. River otters fish in the lake and surrounding wetlands.

Millersylvania State Park's primary ecological treasure is its old-growth forest featuring massive Douglas-firs and western red cedars up to 8 feet in diameter and 250 feet tall. These ancient giants, many exceeding 600 years old, create a multi-layered forest structure with western hemlock filling the understory. Bigleaf maple draped with epiphytic mosses, lichens, and licorice ferns creates a rainforest atmosphere. The forest floor is carpeted with sword fern, vanilla leaf, oxalis, and thick moss layers. Wetland areas around Deep Lake support skunk cabbage, sedges, and moisture-loving shrubs including Pacific willow.

Millersylvania State Park sits on glacial deposits left by the Puget Lobe of the Cordilleran Ice Sheet during the last ice age. The underlying geology consists of Vashon-age glacial till over older glacial and interglacial deposits. Deep Lake occupies a kettle depression formed when a large ice block separated from the retreating glacier, became buried in sediment, and eventually melted, creating a circular depression that filled with water. The lake reaches depths of approximately 60 feet. Soils consist of gravelly glacial till overlain by thick organic layers from centuries of forest accumulation.

Millersylvania State Park experiences a temperate maritime climate typical of the Puget Sound lowlands, with mild, wet winters and warm, relatively dry summers. Annual precipitation averages 50-55 inches, with most falling between October and May as steady rain from Pacific storms. Winter temperatures typically range from 35-50°F, with snow rare and brief. Summer daytime temperatures average 70-80°F, with the forest canopy creating a cool microclimate beneath the trees. Morning fog occasionally develops over Deep Lake. The maritime climate supports the lush temperate rainforest ecosystem.

The Millersylvania area was historically used by Coast Salish peoples, likely the Nisqually and Squaxin Island tribes, for hunting, plant gathering, and seasonal resource use. The massive old-growth trees provided materials for longhouses, canoes, and other traditional uses. European-American settlement began with John Miller, a Civil War general who homesteaded 640 acres in the area in the 1850s. Miller and his family preserved the forest rather than logging it, unusual for the era when most forests were rapidly cleared. The Miller family later donated land that became the nucleus of the state park.

Millersylvania State Park was established in 1921 when the Miller family donated 60 acres of old-growth forest to Washington State Parks, with subsequent acquisitions expanding the park to its current 842 acres. The park was developed during the 1930s by the Civilian Conservation Corps, which constructed many of the buildings, trails, and facilities still in use today. The distinctive CCC-era log and stone structures reflect Depression-era craftsmanship and rustic architectural philosophy. Through subsequent decades, the park expanded campgrounds, improved lake access, and enhanced day-use facilities while preserving the core old-growth forest.

Millersylvania State Park offers over 8 miles of trails winding through old-growth forest and around Deep Lake. The Fitness Trail, a 2-mile loop, provides an easy walk through magnificent old-growth groves where visitors can marvel at Douglas-firs that were saplings before European contact. Interpretive signs explain old-growth ecology. Deep Lake features a swimming beach popular during summer, with a bathhouse and designated swimming area. Non-motorized boats including kayaks and canoes can be hand-launched for fishing and exploration. The park's picnic areas, some with historic CCC-era shelters, provide scenic settings among the ancient trees.

Millersylvania State Park is located approximately 10 miles south of Olympia via Interstate 5 Exit 99, then east on Maytown Road. The park features 167 campsites including sites with full hookups (water, electric, sewer), partial hookup sites, primitive tent sites, and walk-in sites for a more secluded experience. The park also offers 4 cabins for year-round rental. Facilities include modern restroom buildings with showers, dump station, picnic shelters available for reservation, swimming beach with bathhouse, hand-carry boat launch, environmental learning center, and an amphitheater for interpretive programs.

Millersylvania State Park's primary conservation mission is protecting one of the finest remaining lowland old-growth forest remnants in the Puget Sound region. Forest management emphasizes minimal intervention, preserving large trees, standing snags, and downed logs essential for old-growth ecosystem functions. The park removes only hazard trees threatening visitor safety. Lake management addresses water quality concerns from recreational use and surrounding development through monitoring and stormwater controls. Invasive species management targets English ivy, Himalayan blackberry, and other non-natives threatening native plant communities.