Southwest Gas is engaged in the business of purchasing, transporting and distributing the environmental fuel of choice - natu ... ral gas. We serve more than two million customers in Arizona, California, and Nevada. As the largest distributor of natural gas in Nevada and Arizona, we serve the Las Vegas, Phoenix, and Tucson metropolitan areas. In addition, we transport and distribute natural gas in portions of California, including areas in Lake Tahoe and San Bernardino County. read more