Also known as the 1845 Annexation of the Republic of Texas, Texas was admitted to the United States Union as the 28th state on December 29, 1845. On march 2, 1836, Texas declared independence from Mexico. The United States annexed Texas because Mexico wanted Texas, but Mexico didn’t want to add another state that supports slavery. Since the United States annexed Texas, Texas could keep all of its public lands and that the United States would pay 5 million dollars to get them out of debt. Some people said that the annexation of Texas was the manifest destiny for the United States.