Pinal remains Arizona’s fastest growing county

According to the Arizona Commerce Authority, Pinal County grew by 3.7% from July 2024 to July 2025 — far outpacing the next closest county, Yuma, at 1.9%. When boiled down to growth in numbers, Maricopa County — the fourth most populous in the country according to the U.S. Census 2024 stats — assumed more than three times that of Pinal with more than 61,000 new residents. Pinal was second, welcoming more than 18,000.

It’s an exciting time to be in Arizona, according to Craig McFarland, former mayor of Casa Grande and current CEO of Pinal Partnership, a nonprofit focused on planning for Pinal’s developmental future. After eight years as mayor, McFarland has probably been asked to forecast what Pinal’s heavy growth might mean more times than just about anyone else. So what’s one more time?

High growth has all sorts of implications, from the economy to development, housing to water. To McFarland, a community needs energy, water and transportation: “if you don’t have those three, you don’t have economic development.”

Pinal Partnership has been involved in creating a massive transportation plan, with the help of Arizona State University’s computational and analytical tool, the Decision Theater. The Decision Theater will incorporate government data from cities and towns across the county, and factor in population numbers and projections, to spit out some rational options about where future roads and freeways should be placed. The goal is to plan ahead, McFarland emphasized, and to connect all of the growing communities.

The transportation plan hit a roadblock when the tax that was being used to fund the plan was deemed illegal by the Arizona Supreme Court. Now they’re starting over.

That’s where we’re at today, we’re starting to build a new plan,” McFarland said. Details of that plan will become clearer at the end of 2026, he said, as it will take eight to nine months of churning government data and after that, public comment will open.

Pinal County Board of Supervisors Chairman Steve Miller, a longtime supervisor since 2013 and similarly attuned to data points like this, said that the incorporation of San Tan Valley will “change how the county thinks.”

“It takes three or four years to fully see the effects of that and how the county will adjust,” Miller added. “Before the annexation, half of our 500,000 population lived in the cities and towns and half lived in the unincorporated portion of the county. I personally don’t think we, the county, should react too quickly.”

Miller’s caution ran slightly contrary to McFarland’s keen eagerness toward preemptive action. Currently, according to the state’s population numbers from the Arizona Office of Economic Opportunity, Pinal’s 2025 unincorporated population was more than 223,000, about half of the whole county, as Miller said. When San Tan Valley becomes a town, at least 100,000 of those now under the unincorporated umbrella will be counted in the town’s numbers.

Maricopa surpassed Casa Grande as the county’s most populous city in 2018 and remains so in 2025. San Tan Valley will be crowned in that top spot in 2026 once it completes incorporation. Maricopa was the county’s fastest growing city in 2025, with a growth rate of 6.7%. Casa Grande, the second fastest growing, had a rate of 5.3%. Most new Pinal residents moved to those two places, while only about a thousand moved to the unincorporated areas.

Miller spoke from the county’s perspective, where many of those residents will now be under the jurisdiction of the town of San Tan Valley, not directly under Pinal County. “We should wait and see what effects the San Tan incorporation has and what will our level of service and demand really be needed by the county, and how much will be absorbed by the new town government,” he said.

Water will always be an issue in Arizona, McFarland said. As Pinal Partnership’s transportation plan becomes clearer at the end of 2026, the Upper and Lower Basin states of the Colorado River will need to make much headway in terms of negotiation as current agreements expire at the same time. McFarland surmised the federal government will have to force the states into more productive talks.

“I think it’s a good time to be in Arizona,” McFarland said. “I think that we have a lot of opportunity in front of us.”