Snoqualmie Falls is historically significant for its close association with the traditional cultural heritage of the Snoqualmie Indians. The waterfall figures prominently in the origin myth recorded more than 60 years ago by anthropologists. The story told among the Snoqualmie is that Moon the Transformer created the falls from a fishing weir (a fish trap that lets water through) while he was giving shape to the natural environment and the Indian people. The falls have also been identified by some contemporary tribal members as the location of a powerful waterfall spirit and a traditional venue for acquiring spirit power. Although the site of a hydroelectric facility for nearly a century, the falls retain an important place in the culture of the Snoqualmie people. Snoqualmie Falls is within the historic territory of the Snoqualmie Indians and the upper and lower bands of Snoqualmie people had a tradition where upper Snoqualmie people (who lived on the prairies above the Falls) received salmon fishing privileges from people below the falls, while the Lower Snoqualmie people received prairie resources, such as deer, in return. According to several tribal elders, the spirits of the Snoqualmie, divided into prairie and valley spirits, meet at the falls, making this a site of special spiritual power. Snoqualmie Falls was listed in the National Register of Historic Places on October 2, 2009.

Although the Pacific Northwest has many facilities for the generation of hydroelectric power, probably none is as innovative as this one, for the Puget Sound Power and Light Company. It is significant not only as a very early generating facility in the state, but also because of its unusual physical placement and the high percentage of original equipment still in use. Construction of the cavity plant began in 1898 under the guidance of William T. Baker, following his purchase of the property at Snoqualmie Falls the preceding year. He put the facility 250 feet below the surface of the Snoqualmie River, in a dense strata of rock, no doubt prompted by the excellent head of water offered at Snoqualmie Falls, some 270 feet high and with available energy of 30,000 to 100,000 horsepower. Had he erected the plant at the base of the falls, however, the generating machinery would have constantly been exposed to heavy mist and freezing weather. The rock over which the Snoqualmie spills is basaltic and without significant internal cleavage; burrowing the generating plant within this mass kept it completely dry and with a constant year-round temperature, regardless of external weather.

The Snoqualmie Falls Hydroelectric Project was constructed at the end of the nineteenth century to supply the growing demand for electrical power in Seattle and Tacoma. In 1885, the Mitchell and Spalding Company, local agents for the Edison Electric Light Company, secured a 25-year franchise from the City of Seattle to develop an electric utility service using Edison’s incandescent light bulb and electrical equipment. Under the direction of the Seattle Electric Light Company, this became the first central station system for incandescent lighting west of the Rockies and subsequently expanded rapidly to meet growing urban demands for power.