The president exempted a copper smelter in Arizona from air-quality rules. An E.P.A. official guided the company that sought ...

As expected, the deal for the developers of a Tucson data center closed on Christmas Eve, with the transfer of ownership of 290 acres taking place between Pima County and Beale Infrastructure.

Water titans clashed at Caesars Palace in Las Vegas last week, where negotiators from each of the seven Colorado River Basin states outlined what they have done to protect the river—and pointed ...

Saguaro National Park is poised to grow by more than 420 acres, thanks to a pair of recent land acquisitions in the Tucson ...

Negotiations over how to stabilize the shrinking Colorado River are so deadlocked that one of the seven state officials ...