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Company Overview

UniSource Energy Services (UES) provides safe, reliable energy to more than 243,000 customers across Arizona. Our natural gas service reaches about 150,000 customers in northern and southern Arizona, while our electric service reaches more than 93,000 customers in Mohave and Santa Cruz Counties.

UES and its sister company, Tucson Electric Power, are among a family of utilities owned by Fortis, Canada’s largest investor-owned gas and electric utility holding company. Fortis completed an acquisition of UNS Energy Corporation, TEP’s and UES’ parent company, in August 2014.

Electric Service

UES provides electric service in Mohave and Santa Cruz Counties. Our service territory in Mohave County is located in the northwest corner of the state. It includes both Kingman, located in the high desert central portion of the county, and Lake Havasu City, situated in the low desert along the Colorado River.

Our Santa Cruz County service territory serves customers in the south central portion of the state, approximately 60 miles south of Tucson adjacent to the U.S. border with Mexico. We provide service to most of the county, including Nogales - its largest city.

Natural Gas Service

UES provides natural gas service in Santa Cruz, Mohave, Yavapai, Coconino and Navajo Counties.


Fortis is the largest investor-owned electric and gas distribution utility in Canada. Its regulated utilities account for approximately 93 percent of its total assets and serve more than 3 million customers across Canada and in the United States and the Caribbean. Fortis owns non-regulated hydroelectric generation assets in Canada, Belize and Upstate New York. For more information, visit

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