| Union County New Mexico Cities/Towns - Amistad, Capulin, Clayton (County Seat), Des Moines, Folsom, Grenville, Mount Dora, Seneca |
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Your Ad Here Union County is a county located in the U.S. state of New Mexico. As of 2000, the population was 4,174. Its county seat is Clayton. History Union County, was created on January 1, 1894. The county is named "Union" because the citizens were united in their desire for the creation of a new county out of three existing New Mexico counties. ![]() |