Here are the correct matches for the expansion events with their corresponding years:
- Oregon Country (Agreement with Britain): 1846
- The United States: 1783 (Treaty of Paris, which recognized American independence and territory)
- Texas Annexation (Annexed by Congress): 1845
- Alaska (Purchased from Russia): 1867
So the matches are:
- 1846 - Oregon Country (Agreement with Britain)
- 1783 - The United States
- 1845 - Texas Annexation (Annexed by Congress)
- 1867 - Alaska (Purchased from Russia)