Air Force eyes reactivation of dormant Montana missile field as Sentinel project grows in scope

The Air Force is exploring the reactivation of a north-central Montana nuclear missile field, roughly the size of Rhode Island, as part of the Department of Defense’s Sentinel project to replace the land-based arsenal of intercontinental ballistic missiles, or ICBMs.

The area under consideration includes 50 missile silos that make up the 564th Missile Squadron, which spans the area between Dutton and Shelby and was officially deactivated in 2008. The proposed reactivation of the 564th has recently been included in a supplemental environmental impact statement being prepared by the Air Force.

The proposal would be yet another expansion of the $140 billion Sentinel project, which has already seen delays and a pivot toward digging new silos after initially planning to use the original ones. A government review was ordered in 2024 after project costs grew by 81%. The U.S. Government Accountability Office said earlier this year that the current fleet of Minuteman III missiles could remain on alert through 2050 — 14 years longer than initially planned. 

The Sentinel missile, under development by Northrop Grumman, is the modern replacement for the Minuteman.

Malmstrom Air Force Base in Great Falls plays a major part in Sentinel. The base is home to the largest of the three missile wings and has kept the Minuteman missile fleet on alert continuously since 1962. The active missile field managed by Malmstrom consists of 150 silos across rural central Montana. The other two missile wings operate out of F.E. Warren Air Force Base near Cheyenne, Wyoming, and Minot Air Force Base in North Dakota.

The Air Force deactivated the 564th Missile Squadron in 2008 as part of the New START Treaty with Russia to pare down nuclear arsenals. Over several years, crews removed equipment from the missile silos and filled them with dirt and gravel.

The missile sites, often a half-dozen acres of land carved out of a farmer’s field, are still owned by the Department of Defense and have extra, unused land to spare. Tom Kuka, a Pondera County commissioner, told Montana Free Press that crews have been out doing land surveys and taking soil samples.

Kuka said that locals aren’t expecting too much disruption from Sentinel construction. Similarly, he’s not expecting a windfall from new land transactions if the Air Force builds on sites it already owns.

That reflects conversations that journalist Taylor Barnes had with landowners in north-central Montana this fall. Barnes, who covers the defense industry for Inkstick Media, visited some of the deactivated sites during her trip, using a yellowed guidebook made by anti-nuke activists in the ’80s to navigate the backroads.

“It had these instructions like, ‘Go down this gravel road for three miles and then turn east and go a mile and a half,'” Barnes told MTFP.

Many of the sites were little more than fenced areas with concrete slabs.

Barnes said that landowners she spoke with viewed the presence of nuclear missile sites as fairly pedestrian. She heard more interest in the prospect of solar panel or wind farm developments, which can be more lucrative for farmers and ranchers.

“They also said in their day-to-day lives, it didn’t matter much,” Barnes said. “They said when the military deactivated the field, they didn’t really care.”

One of the most tangible impacts cited by Kuka and fellow commissioner Jim Morren is the quality of the rural roads. They said the Air Force paid the county to maintain roads used to access missile sites, and that led to some quality gravel or pavement.

“My goodness, that road is fantastic when you get to where the missile is,” Morren said.

Still, many details are subject to change with Sentinel. During a 2025 town hall meeting, Air Force representatives seemed to backtrack on some details from the initial 2023 environmental assessment. Plans for workforce hubs that originally projected 3,000 workers around Great Falls and Lewistown have changed, representatives said in 2025. The project shifted to constructing new missile silos rather than the original ones. 

The forthcoming supplemental environmental impact statement is in progress but isn’t expected to be completed until the spring of 2028. Items under consideration include reactivating the 564th Missile Squadron and acquiring land for up to 30 new launch sites in Montana. That’s part of some 120 new sites proposed across the three missile fields — yet another expansion.

To explain the need for a supplemental environmental impact statement, the Air Force acknowledged the move toward newly built silos. One statement said that retrofitting existing missile infrastructure was unlikely “as key Sentinel program milestones were no longer achievable based on cost and schedule risks associated with converting existing [launch facility] sites to Launch Silo (LS) sites.”

There are political considerations as well. New START, a 2011 treaty that led to the deactivation of the 564th missile field in Montana, expired in February 2026. Over time, political changes in Congress or in the presidency — along with developments in international nuclear diplomacy — could change the trajectory of the Sentinel project.

“These missiles in the past have been undone by shifting political currents,” said Barnes, the defense journalist.

She noted that in 1991, President George H.W. Bush took unilateral action to take hundreds of nuclear weapons off alert. As part of the first Strategic Arms Reduction Treaty (START) that same year, 150 nuclear missiles were removed from their silos and deactivated.

The Sentinel project has already spanned three presidential administrations and is all but certain to last through more.