Which brought large numbers of white and chinese people into northern oregon in the 1850s? the promise of free land for all races the building of railroads the discovery of gold warfare with native americans

Discovery of gold--the chance to find gold and strike it rich brought diverse populations to the west coast. 

Following the rush in California in 1849, the area continued to be explored. About a year later gold was found in Oregon sending populations of miners to Oregon to mine.