Oregon Republican Party emerged in the 1850s during the national anti-slavery realignment that helped create the Republican Party.   Oregon's GOP was a leading anti slavery party opposed to the proslavery Democrats of the state.  In Oregon, the Republican organization took shape in 1856 and was formally established in 1857 as the “Free State Republican Party of Oregon”.  The party’s early growth was tied to Oregon’s transition from territory to statehood. Republicans held their first state convention in 1859, and in 1860 they helped elect Edward Dickinson Baker as Oregon’s first Republican U.S. Senator, marking the start of a long era of Republican influence in the state.  The Umatilla County GOP  was created on September 27, 1862, from part of Wasco County, during the same Civil War-era period when Oregon Republicans were becoming a major political force.  The county’s history is closely tied to eastern Oregon’s settlement patterns, agricultural development, and the rise of towns like Umatilla and Pendleton.   That matters because Umatilla County became one of the strongest Republican areas in Oregon.  Like much of eastern Oregon, the county has long leaned Republican, and its voters have often given the party a strong advantage in statewide and national elections.