Answer:
The standard term used for a wild hog in the United States is feral hog or feral pig. Feral means it was once domestic and is now wild. Spanish explorers brought domestic hogs with them in the 1500's and they have spread across the country. Many states now have populations of wild hogs but the southeastern states, as well as Texas have very large populations.
Wild boar is usually the term used for the Eurasian wild boar, originally from Russia. It has also been brought to the United States and has freely bred with the feral hog population. The Eurasian wild boar is larger, huskier, and more aggressive than other wild hogs.