Rainbow Valley is a watershed located on Turnagain Arm between Rainbow Peak to the west and Indianhouse Mountain to the east, approximately 17 miles (27 km) south-southeast of Anchorage and 17 miles (27 km) west-northwest of Girdwood, Alaska. The watershed is drained by Rainbow Creek, which originates from snowfields at an elevation of 5,000 feet on a mountain formerly known as Suicide Peak. The peak’s name was recently changed to the Dena’ina Athabascan name Yuyanq’ Ch’ex, meaning “Heaven’s Breath.”  The creek flows southwest for 3 miles to the northern shore of Turnagain Arm on Cook Inlet. The name “Rainbow Valley” was first used by local gold prospectors and was reported in 1898 by George F. Becker of the U.S. Geological Survey.

In 1895, the gold mining districts of Hope and Sunrise were founded on the southern shore and near the head of Turnagain Arm. The nearest deep-water ports were in Passage Canal on Prince William Sound, Seward on Resurrection Bay, and Seldovia in Kachemak Bay. Prospectors would travel over Portage Pass from Prince William Sound or the Resurrection Pass Trail from the Kenai Peninsula to reach Hope and Sunrise. From Hope, they used boats to cross Turnagain Arm and access several creeks on the northern shore, such as Rainbow Creek, where the mist on sunny days creates a rainbow effect. Other gold prospects on the northern shore included Indian Creek, Bird Creek, and Crow Creek.

From 1915 to 1918, railroad construction crews surveyed the Turnagain Arm section of the Alaska Railroad, blasting over 30 miles (48 km) of rock and building a series of long bridges. Rainbow became a supply camp and later a section house, with a spur line accommodating about 22 cars. In 1919, Rainbow was designated a flag stop in the Railway Guide Index, attracting homesteaders to the valley. Today, the homesteads have been subdivided into an off-grid community of about 17 homes along an unpaved road that winds steeply uphill, surrounded by Chugach State Park. A popular hiking trail, approximately 5 miles (8 km) long, ascends about 3,450 feet (1,050 m) to the summit of Rainbow Peak. Read more here and here. Explore more of Rainbow Valley and Turnagain Arm here: