 He left in May and arrived in November of what was still the unorganized Oregon Country . At this time the region was under the jurisdiction of the United States after the settling of the Oregon boundary dispute with Great Britain the previous year . In Oregon , Chapman settled first in what was then Marysville , and is now Corvallis , in the Willamette Valley . In 1848 , he relocated to Salem , where he learned of the California Gold Rush while at court at Knox Butte . Chapman went to California for a brief time and had some success in the gold fields before returning in 1849 to Oregon , which had become the Oregon Territory in 1848 . 
