First explored by the Spanish in the 16th and 17th centuries, the region was added to the United States through the Louisiana Purchase (1803) and a cession by Mexico (1848).

• 于16和17世纪首先被西班牙人探险发现，通过路易斯安那购买（1803年）和墨西哥的割让（1848年）而加入美国版图。