The tribes of the western Oregon were quite numerous, previous to contact with traders and explorers to the North West Coast. Outsiders, brought numerous diseases which were the greatest factor in eliminating their large populations. The first diseases were likely small pox and influenza. Lewis and Clark’s expedition (1805-1806) encountered victims of small pox in 1805 on the Columbia. By 1830, malaria was a factor in Oregon, with epidemics happening as early as 1829. Malaria was likely the most destructive of all of the diseases and caused some 90%  decline in populations, such that by 1850, the tribes of the … Continue reading Early Counts of Western Oregon Tribal Peoples