Record-breaking heat and historic drought in the U.S. West are doing little to discourage cities from planning to welcome millions of new residents in the decades ahead.

From Phoenix to Boise, officials are preparing for a future both with more people and less water, seeking to balance growth and conservation. Development is constrained by the fact that 46% of the 11-state Western region is federal land, managed by agencies like the U.S. Forest Service and Bureau of Land Management that are tasked with maintaining it for future generations.