I suppose the two "white" counties didn't exist yet?
Deschutes and Jefferson counties were formed from Crook County, the county to the east.
In 1914, there was an election to move the county seat from Prineville, today still the county seat of Crook County, to Bend, the largest city in what became Deschutes County, it failed by 2.5%. In response Deschutes County was created with Bend as county seat (Jefferson County had been set off earlier). The railroad came to Bend in 1914, which enabled large scale logging to occur and by 1920, Deschutes County had a much larger population than either Crook or Jefferson counties. In 1910, it is less clear. At that time Prineville at around 1000 had about twice the population of Bend.
