Colonial Creek Campground

Overview

Set in old-growth forest on the shores of Diablo Lake at milepost 130 on WA-20, Colonial Creek Campground is the park’s "remote yet bustling" basecamp. The setting is classic North Cascades—towering cedars and hemlock, blue-green water, and trailheads you can walk to from your site.

North vs. South Loops

• North Loop: Smaller (about 37 sites) and generally not large‑RV friendly. Direct access to the Thunder Knob Trail, which delivers big views of Diablo Lake.
• South Loop: Larger (about 93 sites) with some lakeside spots, the RV dump station, and the Thunder Creek Trailhead across the road.

Campsites and Amenities

Every site has a picnic table, bear box, and fire ring. Both loops have drinking water and flush toilets. There are no electrical hookups or showers, and many pads are uneven gravel. An RV dump station is in the South Loop. Typical limits are up to 8 people, 3 tents, and 2 vehicles per site.

Services are minimal—no firewood, ice, or gas at the campground—so plan to stock up before you arrive (nearest services are in Marblemount). Unreserved sites during peak season can sometimes be claimed same day for one night only.

Activities

• Hiking: Walk to Thunder Knob (views) from the North side and Thunder Creek (lush river hiking) from the South side.
• On the water: There’s lakeshore access plus a boat launch and a fishing pier in the campground area. Kayaking and canoeing are popular; a Washington State fishing license is required to fish Diablo Lake.

Wildlife and Safety

Black bears are active here—use the provided bear boxes and keep a clean camp. The area is part of a hydroelectric project with a high‑water warning system; follow posted guidance. On the lake, expect very cold water; winds can rise quickly, and currents can be strong—wear a life jacket.

Nearby

Make quick side trips to Diablo Lake Overlook (about 1.5 miles east), Ross Lake Overlook (about 5 miles east), and the North Cascades Visitor Center (about 11 miles west).

Reservations and Season

Peak season runs late May through early September and requires reservations. Booking is staggered: in the North Loop, sites 1–35 release 6 months out and 36–43 release 7 days out; in the South Loop, most sites release 6 months out, with a smaller block 7 days out. Outside peak, parts of the campground may operate first‑come, first‑served; in the South Loop, ten walk‑in tent sites are FCFS before and after peak season.

Best Time to Visit

Midweek in June or September strikes the balance between open sites and good weather. Arrive early in the day for better site selection and calmer paddling conditions. For photography, mornings and late afternoons give softer light on Diablo’s turquoise water.