The Farmington Electric Utility System is a municipally operated system located in northwest New Mexico with a service territory of 1718 square miles encompassing the City of Farmington, most of the populated area of San Juan County (including the City of Bloomfield and the San Juan River Valley west from the City to the Navajo reservation) and a portion of Rio Arriba County northeast of the City. The Electric Utility also provides transmission services for the City of Aztec, which owns its own substation and distribution facilities and to Williams Field Services to wheel the generation output of their Milagro facility to the Shiprock Substation for sale in the western markets. As of fiscal year ended December 31, 2006 the Electric System served approximately 43,000 customers.