Las Vegas, often known simply as Vegas, is a city in and the county seat of San Miguel County, New Mexico, United States. Once two separat…Las Vegas, often known simply as Vegas, is a city in and the county seat of San Miguel County, New Mexico, United States. Once two separate municipalities, both were named Las Vegas: West Las Vegas and East Las Vegas. They are separated by the Gallinas River and retain distinct characters and separate, rival school districts.