Bonjour,
Réponse :
1. Last parts of Maine and Michigan ceded by Great Britain.
2. Annexation of the states of Wyoming and Colorado by the US from the Cherokee tribe.
3. Gadsden Purchase.
4. Treaty of Paris: The US gained 11 new states just west of the original colonies.
5. Mexican Cession: the US gained Utah, Nevada, California and Arizona.
6. Texas Annexation
7. Louisiana Purchase: France sold it to the US.
8. Treaty with Great Britain: The US gained the "Oregon Country", which includes the states of Washington, Oregon and Idaho.
9. North Dakota ceded by Great Britain (with parts of Minnesota and South Dakota).
Intru: Cession of Florida by Spain.
Voilà! Bonne journée!