Yes, and south, too. With border counties in Texas infested, they have spread into northern Mexico. Their northward spread depends on temperature. Cold winters tend to push them back. Western spread is largely dependent on water. They will mostly be found in urban areas, creek bottoms, irrigated land, and other areas where moisture occurs. The entire Pacific Coast is fertile ground for infestation. The quarantine (certification of plant material shipped outside the fire ant zone) slows the spread. To see where the imported fire ants are, please look at the APHIS USDA - U.S. quarantine map. See also: FAQ #1097: "How do imported fire ants spread from location to location? How far can they travel?" and FAQ #809: "What is the government doing about imported fire ants?"