Amap showing the continental united states. areas designated on the map include the original 13 colonies, the florida territory, the louisiana purchase, the texas annexation, mexico, the mexican cession, the oregon territory, the gadsden purchase, and the british cession of 1818. review the map above. how did the idea of manifest destiny affect the u. s. border throughout the 1800s? a. the border of the u. s. remained the same until the late 1890s. b. the border of the u. s. expanded all the way to the west coast. c. the border of the u. s. shrank as other countries returned to colonization. d. the border of the u. s. expanded to contain large amounts of land in canada.