The Mexican War was a conflict between the United States and Mexico that occurred in the mid-19th century and resulted in the United States acquiring a large portion of land from Mexico. The War on Terrorism is an ongoing global effort to combat terrorism and extremist groups that began after the September 11, 2001 attacks on the United States. The Mexican War was a conventional conflict between two states, while the War on Terrorism is an unconventional conflict against non-state actors. The Mexican War had clear beginning and end points and was fought primarily in North America, while the War on Terrorism is ongoing and has involved military operations in multiple regions around the world.