 After the region was organized within the Oregon Territory with the current northern border of 49°N, Vancouver County was renamed Clarke, and six more counties were created out of Lewis County before the organization of Washington Territory in 1853; 28 were formed during Washington's territorial period, two of which only existed briefly.The final five were established in the 22 years after Washington was admitted to the Union as the 42nd state in 1889.Article XI of the Washington State Constitution addresses the organization of counties.