In the 1830s a “fever and ague,” later determined to be malaria, devastated Native Americans living on the mid and lower Columbia River, and in the Willamette Valley. More than eighty percent of the Cascade Indians were killed by the epidemic.
Surviving Cascade Indians continued to live on the Columbia River, harvesting salmon during the seasonal migrations. Some Cascades lived part of the year outside Fort Vancouver. In 1855, Cascade Indians were accused of joining the Yakama and the Klickitats in an attack on Fort Cascades. The blockhouse had recently been built at the Cascades Rapids after war broke out between the US Army and Native Americans on the Columbia Plateau. An Indian confederation, which evidence suggests did not include the Cascade Indians, captured Fort Cascades, but was defeated by US army troops the following day. Settlers and army members murdered, held captive, and hung many Cascades as a result of the attack. The war, which became known as the Yakima War, was instigated when miners invaded Plateau Indians’ land.
Some of the few remaining Cascades were moved to the Yakama and Warm Springs reservations. Others lived in off-reservation Indian communities, or continued to live on the banks of the Columbia. American homesteaders further displaced the Cascades by moving into traditional Indian homelands.
