New Spain
noun
the former Spanish possessions in the Western Hemisphere, at one time including South America (except Brazil), Central America, Mexico, the West Indies, Florida, and most of the land in the U.S. west of the Mississippi River.
British Dictionary definitions for new spain
New Spain
noun
a Spanish viceroyalty of the 16th to 19th centuries, composed of Mexico, Central America north of Panama, the Spanish West Indies, the southwestern US, and the Philippines