The Hudson's Bay Gristmill Site on the Colville River, listed on the National Register of Historic Places in 1982, represents a pivotal chapter in the early agricultural and industrial development of the Pacific Northwest. Established in 1843 by the Hudson's Bay Company (HBC) under the direction of Chief Factor Archibald McDonald, the gristmill was built to support the nearby Fort Colvile, which served as the agricultural heart of the HBC's Columbia Department. Located on the Colville River in Stevens County, Washington, this water-powered mill replaced an earlier, smaller mill and utilized massive, imported millstones to grind wheat grown by local settlers, Native Americans, and the company itself. The site stands as a physical testament to the transition of the region from a purely fur-extracting economy to a permanent, diversified agricultural settlement.

Historically, the mill held immense regional significance as a primary supplier of flour and foodstuffs for the extensive network of HBC fur trading posts, inland brigades, and expeditions stretching north into New Caledonia (present-day British Columbia). Because Fort Colvile was strategically situated at a geographic crossroads, the gristmill played a crucial role in ensuring the food security and economic self-sufficiency of the British empire's western operations during a period of intense geopolitical competition with the United States. Today, as an archaeological site, the Hudson's Bay Gristmill Site offers invaluable insights into early 19th-century industrial technology, trade networks, and the multicultural interactions between European traders, American settlers, and the native Spokane and Colville tribes who frequented the area.

The Kettle Falls Archaeological District, spanning the Columbia River between Ferry and Stevens counties, Washington, represents one of the most culturally and historically significant Indigenous sites in the Pacific Northwest. For over 9,000 years, the roaring cascades of Kettle Falls served as a vital ecological and cultural epicenter for the Salish-speaking peoples of the Columbia Plateau, particularly the Colville, Spokane, Kalispel, and Sanpoil tribes. As the second-largest salmon fishery on the Columbia River, the falls attracted thousands of Native Americans annually during the seasonal salmon runs. This massive convergence transformed the area into a major hub for intertribal trade, diplomatic councils, social games, and spiritual ceremonies. Although the physical falls and surrounding encampments were inundated in 1940 by the reservoir of the Grand Coulee Dam (Lake Roosevelt), the district remains a sacred ancestral landscape of immense cultural importance.

In the early 19th century, the existing Indigenous trade networks at Kettle Falls naturally drew Euro-American explorers, fur traders, and missionaries to the area. Canadian explorer David Thompson arrived in 1811, and by 1825, the Hudson's Bay Company had established Fort Colvile nearby, which quickly became the most profitable inland fur-trading post in the Columbia Department. This was followed by the establishment of St. Paul's Mission in 1845 to minister to the tribes gathering at the fishery. Extensive archaeological excavations, conducted primarily before the reservoir was filled and during subsequent seasonal drawdowns, have yielded rich assemblages of projectile points, fishing gear, and trade goods. These resources have provided researchers with invaluable insights into the technological adaptations, trade patterns, and enduring cultural resilience of the region's inhabitants over millennia.

The Old Indian Agency, located near Chewelah in Stevens County, Washington, stands as a highly significant historical landmark representing the early federal administration of Native American affairs in the Pacific Northwest. Established in 1872, the rustic log and wood-frame structure served as the headquarters for the Colville Indian Agency during a critical transitional era. As one of the oldest remaining governmental buildings associated with the Bureau of Indian Affairs in the state of Washington, the agency building preserves a tangible link to the complex history of regional treaty negotiations, land division, and early pioneer settlement in the Colville River Valley.

Under the stewardship of Major John A. Simms, who served as the Indian Agent from 1872 to 1883, the Chewelah agency was the administrative center for the Colville, Spokane, and other regional tribes. From this modest building, Simms managed government relations, distributed annuities, and implemented the federal policies that ultimately relocated area tribes onto designated reservations. The building's survival offers invaluable insight into the federal government's nineteenth-century tribal policies and stands as a poignant monument to both the cultural displacement and the enduring resilience of the region's indigenous peoples.