Provisional and Territorial Records Guide
Note: The following map is intended to provide researchers with a general understanding of significant county boundary changes over time. Researchers should refer to other sources for more detailed and precise representations.
County boundaries in 1843 (present Oregon boundaries shaded):
When the Oregon Provisional Government was formed on July 5, 1843, its white population stood at roughly 880 men, women and children. This colony inhabited four counties comprising an area bounded by latitude 54'40" on the north, by the crest of the Rockies to the east, by latitude 42' on the south, and by the Pacific Ocean to the west. This region included the present-day states of Idaho, Oregon and Washington; portions of Montana and Wyoming; and half of the province of British Columbia. The state of Oregon is shown by the shaded region.