Oregon Country: Not Acquired by Treaty—Jointly Claimed, Then Divided

No Single Acquisition Date

The Oregon Country (Columbia District to the British) was never purchased or conquered. Instead:

1. Overlapping Claims (1818–1846)

• U.S. – Based on Gray’s Columbia River entry (1792), Lewis & Clark (1805), Astoria fur post (1811).
• Britain (HBC) – Fur-trade network, forts (Vancouver, Victoria).
• Russia – South to 51°N (ceded 1824/25).
• Spain – Ceded north of 42°N (Adams-Onís 1819).

2. Joint Occupation (1818 Treaty)

U.S. & Britain agreed to joint occupancy for 10 years (renewed indefinitely). No sovereignty—just shared access.

3. "54°40′ or Fight" & the 1846 Treaty

• Polk campaign slogan demanded all territory to Russian Alaska (54°40′N).
• Compromise: 49th parallel to the Strait of Georgia, then mid-channel to Pacific.
• Oregon Treaty signed June 15, 1846; ratified June 18; proclaimed July 17.

4. Result

• U.S. gains: Future WA, OR, ID, MT (west of Rockies), WY (small).
• Britain retains: Future BC (including Vancouver Island whole).
• No money changed hands; HBC posts gradually sold/transferred.

Key date: June 15, 1846 (treaty signing)—but it was a boundary settlement, not an acquisition.