The North Cascades Highway—State Highway 20—begins in the Skagit River Valley , and follows this drainage to 5,477-foot Washington Pass, before descending into Methow Valley  on the east side of the Cascade Range.
Along the way, the road passes several small towns—Sedro-Woolley , Concrete , Rockport , and Marblemount —but after this you enter North Cascades National Park  and Okanogan National Forest lands. This is magnificent mountain country, with numerous pullouts for viewing the striking scenery and a multitude of recreation options—campgrounds, visitors centers, and access to many other hiking paths, including the Pacific Crest Trail.
Because of this, Highway 20 is one of the most popular and scenic drives in Washington. But don’t plan on just driving through; bring your hiking boots, map, and a flexible schedule to really experience the North Cascades. Highway 20 is also a popular cycling route in the summer months, providing an official Bikecentennial route across rural America from Anacortes, Washington , to Bangor, Maine.
Highway 20 joins Highway 153 at Twisp , Highway 97 near Pateros, and Highway 2 near Wenatchee  to form the northwest portion of the “Cascade Loop.” This 400-mile scenic drive winds through the North Cascades, past Lake Chelan , through Leavenworth  on its approach to Stevens Pass , and returns to western Washington and Whidbey Island . You’ll find free Cascade Loop booklets at visitors centers along the way, or ask the Cascade Loop Association (509/662-3888, www.cascadeloop.com ) in Wenatchee for a copy.
A similar promotional highway route is called the North Cascades Loop. It follows the same route over Highway 20, continues on to the twin towns of Omak and Okanogan, turns north on Highway 97, and goes across into British Columbia ’s Okanagan (note that Canada and the U.S. spell the word differently), then heads west on the Trans-Canada Highway to the Vancouver area. Look for free International Loop booklets at visitors centers.
Summer weather on the west side of the North Cascades is cooler and wetter than the eastern portion, which is protected by the rain-shadow effect. The east side of the range gets quite hot in the summer and is usually dry. One of the major attractions of the Methow Valley for Puget Sounders is the usually sunny weather, the cold Colorado-style winters, and the hot, dry summers that make a perfect antidote to the damp, often overcast Puget Sound weather.
No gas stations, restaurants, or other facilities (except restrooms at Washington Pass) are found along the 75 miles of Highway 20 between Ross Dam and Mazama, so fill up when you leave I-5 (Sedro-Woolley  is cheapest if you get lots of miles per tank). No bus service goes along this route either; the closest you’ll get is Mount Vernon  on the west and Pateros and Okanogan on the east.
The middle section of Highway 20 closes for the winter after the first major snowfall because of avalanche danger. It is usually gated in late November and doesn’t open again until late April, sometimes nearly June, depending on the amount of snow. In mid-winter, snow depths can exceed 15 feet at the summit. Parts of the highway remain open to snowmobile traffic from Colonial Creek Campground on the west side to Early Winters Campground near Mazama. Lower- elevation hiking trails, such as those along Ross Lake , are generally accessible from April through mid-October; at higher elevations, trails are usually snow-free from mid-July through September.