[1][2] The counties of Ada, Adams, Boise, Canyon, Elmore, Gem, Owyhee, Payette, Valley, and Washington are included in the region.

Southwestern Idaho was originally inhabited by three main Native American tribes: the Shoshone-Bannock, the Nez Perce, and the Northern Paiute.

[5] The Native Americans tribes were nomadic, adopting a hunter-gatherer lifestyle, and had an annual rendezvous in the Boise Valley, which also included catching salmon.

Mountain men, including Spaniards and Mexicans, lived off the land in Southwestern Idaho, trading with the Native Americans in the area.

The Payette Lake, a beautiful sheet of water 12 miles long, in places is dotted with richly wooded inlets set like emerald gems on the bosom of the liquid mirror.

In a few years, commercial fisheries would come to operation on Payette Lake, selling fresh, salted, and dried Chinook salmon and white fish to the areas in the Boise Valley.

Over time, infrastructure, including a hotel, the Meadow-to-Warren Trail (now Idaho State Highway 55), and a post office led to the southern shore of Payette Lake to become the center of mining, recreation, forestry, and agriculture for the McCall area.

Rapid and exponential growth was relatively contained by the limits of agriculture and irrigation over the next half century, as Southwestern Idaho has an arid climate that makes long-term, practical farming difficult.