Seaquest State Park campground
State Park ~2 hr 30 min from Seattle

Seaquest State Park

Year-round Mt. St. Helens base camp with 15 full-hookup, 18 water & electric, and 52 standard RV sites. A pedestrian tunnel connects directly to the Mt. St. Helens Visitor Center.

RV Sites
85
total sites
Max Length
50 ft
full hookups
Hookups
Full Hookups
full hookups
Surface
Gravel
site surface
Dump Station
On-site
Available to all registered campers
Reservation
6 mo.
books out fast
Why Visit

Seaquest State Park

Seaquest State Park is the ideal base camp for Mount St. Helens, sitting in old-growth fir forest with a pedestrian tunnel running under Highway 504 directly to the Mount St. Helens Visitor Center. Fifteen full-hookup sites and 18 water-and-electric sites accommodate RVs up to 50 feet, with flush restrooms, a dump station, and Silver Lake boat access just across the highway. The park operates year-round with diverse campsite options including five yurts.

3030 Spirit Lake Hwy, Castle Rock, WA 98611
~2 hr 30 min from Seattle (150 mi)
Online reservation · Reserving 6 months in advance
Discover Pass required
Washington state map showing Seaquest State Park location
Open in Google Maps Castle Rock, WA
Campground Specs

Details that matter for your rig

Maneuverability
Challenging
Tight loops — plan your approach
Cell Coverage
Spotty
Download maps before you go
Generators
Restricted
Designated hours only
Site Surface
Gravel
Check conditions at check-in
Dump Station
On-site
Available to all registered campers
Hookups
Full Hookups
Full W+E+S hookups
Things to Do

Activities at Seaquest State Park

🥾 Hiking 🎣 Fishing 🏊 Swimming 🚣 Kayaking 🏖️ Beach ⛵ Boating 🛝 Playground

On-site & nearby activities

  • Mt. St. Helens Visitor Center via park tunnel
  • Silver Lake kayaking and fishing (across highway)
  • Hiking in Mount St. Helens National Volcanic Monument
  • Castle Rock Exhibit Hall geology displays
  • Wildlife viewing in forest and lake areas
  • Johnston Ridge Observatory day trip (50 miles)
State Park

Washington State Parks — built for exploration

Seaquest State Park sits directly across Silver Lake from the Mount St. Helens National Volcanic Monument visitor center, in the shadow of the volcano that catastrophically erupted on May 18, 1980 — an event visible and audible across half of Washington State. The surrounding landscape represents one of the world's most closely studied examples of post-volcanic ecological recovery, where elk, black bear, and wolves have returned to terrain that was stripped of all life in 1980. Silver Lake itself is one of western Washington's most productive warm-water fisheries, with largemouth bass and yellow perch in a shallow, weed-rich lake that also supports nesting osprey, great blue herons, and migratory waterfowl in the shadow of the volcano.

Facilities

What's on-site

🚻
Toilets
Flush toilets
🚿
Showers
Not available
💧
Drinking Water
Available
🔥
Fire Pits
Every site
Flush toilets and drinking water are available, but no showers on site. Every site includes a fire pit.
Insider Knowledge

Site recommendations from the field

Sourced from first-hand visits, park ranger notes, and RV community reports. Updated when conditions change.

🗺️

Sites on the Silver Lake loop (1–30) are best for lake access and fishing. Hookup sites in the upper loops are well-equipped for extended stays. The park's location directly across from the Mt St Helens Johnston Ridge Observatory Visitor Centre (free day-use access) is the major draw. Sites 1–15 nearest Hwy 504 can have some road noise; request an upper loop site for quiet nights.

Logistics

Nearest services

📍 Nearest TownCastle Rock, WA
⛽ Gas Station5 mi
🛒 Grocery Store5 mi
🏪 Costco50 mi
☕ Starbucks15 mi
🏕️ Nearest State Park22 mi

Stock up in Castle Rock, WA before heading out — services get limited near the campground.

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Ready to book?

Ready to book Seaquest State Park?

Check availability online. Reserving 6 months in advance.

Reserve a Site
Information sourced from official park agencies and publicly available data. Conditions, fees, and availability change — verify details directly with the campground before your visit.