The park's name is a compound word derived from the original homesteading Miller family and the Latin suffix 'sylvania', meaning 'woods'.
Much of the park's iconic rustic architecture was constructed by the Civilian Conservation Corps between 1935 and 1938.
Deep Lake, the primary water feature, is a kettle lake formed by retreating glaciers during the last ice age.
The park contains one of the last remaining old-growth stands of timber in the region, including trees estimated to be hundreds of years old.
The park operates a dedicated retreat center known as the Environmental Learning Center, which is often used for group educational programming.
Millersylvania State Park is a 903-acre forested recreational area located along the shores of Deep Lake in Washington State. The park features old-growth forests, specifically stands of Douglas fir and western red cedar, which distinguish it from neighboring younger landscapes. Established on land once owned by the Miller family, it was developed by the Civilian Conservation Corps (CCC) during the Great Depression. The park's infrastructure retains significant examples of rustic-style CCC architecture, including kitchens, picnic shelters, and administrative buildings built from native timber and stone. Visitors have access to seven miles of hiking trails and miles of bicycle trails that traverse dense canopy. Deep Lake provides water-based recreation including swimming, boating, and fishing for rainbow trout. The park maintains a year-round camping facility with over 100 campsites and utility hookups. Its location within a temperate rainforest zone contributes to its lush, moss-covered understory.
The CCC-built kitchen shelters or the reflection of the old-growth trees on the calm surface of Deep Lake at sunrise.
Bring a Discover Pass, as it is required for vehicle access to all Washington State Parks.
Pack insect repellent during the summer months, as the proximity to Deep Lake results in high mosquito activity.
Utilize the designated swimming area at the lake rather than swimming near the boat launch for safety.
Do not attempt to swim in areas designated for boat traffic only. Avoid visiting on peak summer holiday weekends without a prior camping reservation, as the park reaches capacity early.
The park is open year-round for day use and camping, though some individual campsites may be closed during the winter season for maintenance.
Leash your pets at all times; observe quiet hours in camping areas; practice Leave No Trace principles to protect the forest ecosystem.
