These installations form a critical component of the United States’ nuclear triad, which consists of land-based missiles, submarine-launched ballistic missiles, and long-range strategic bombers. Together, these systems are designed to ensure deterrence by maintaining the capability to respond to a nuclear attack.

Because ICBM silos are fixed in place, widely documented, and concentrated in specific geographic areas, they are frequently included in scenario modeling as potential targets in a theoretical nuclear exchange. Their inclusion in these models does not imply that they are currently being targeted; it simply reflects their strategic importance in defense planning.

Research conducted by the Princeton Program on Science and Global Security, in collaboration with the Brown Institute for Media Innovation, indicates that the United States maintains hundreds of land-based nuclear missiles housed in underground silos across five states: Montana, North Dakota, Wyoming, Nebraska, and Colorado.

Out of roughly 450 missile silos nationwide, about 400 are believed to contain operational nuclear missiles as part of the country’s deterrence structure. Because the locations of these installations are publicly known and fixed, they often serve as the foundation for simulations that explore the potential spread of fallout and other consequences in an extreme conflict scenario.

Defense scholars widely recognize that missile silos, by their very nature, are vulnerable in theoretical first-strike scenarios. Their fixed positions make them easier to locate compared to mobile or submarine-based systems. For this reason, they are maintained under constant monitoring by the U.S. Air Force, and the nation’s Strategic Command (STRATCOM) continuously oversees their operational readiness.

Nuclear Fallout Modeling: How Scientists Study Potential Risk

To better understand how radioactive material might spread following a nuclear detonation, several academic and research institutions have developed sophisticated modeling systems. These models rely on real meteorological data, atmospheric transport algorithms, and advanced computer simulations to estimate how radioactive particles could move through the environment.

One notable study titled Under the Nuclear Cloud, supported by researchers at Princeton University and Columbia University, uses historical wind data and particle transport software to simulate how fallout could disperse across North America after a coordinated strike on missile silo fields.

According to these simulations, residents of states such as Montana, North Dakota, South Dakota, Nebraska, and Minnesota could experience radiation exposure exceeding one gray (Gy) under certain conditions. This level of exposure is generally associated with serious health effects and, in severe cases, could prove fatal without protective shelter.

Other modeling work, including analyses published by Scientific American, has produced maps demonstrating how radioactive particles carried by wind currents could travel far beyond the initial target zones. In these scenarios, fallout might spread across vast areas of the United States and potentially reach parts of Canada and Mexico depending on atmospheric conditions.

Researchers emphasize that such studies are not forecasts of real events. Instead, they are designed to help policymakers, scientists, and emergency planners better understand possible outcomes, evaluate vulnerabilities, and develop strategies for disaster response in the unlikely event of a nuclear crisis.

Regions Often Highlighted in Modeling

Even in purely hypothetical scenarios, experts consistently stress that no region of the country could be considered entirely safe in a large-scale nuclear conflict. When analysts discuss “safer” or “lower-risk” areas, they are referring only to comparatively lower levels of projected radiation exposure within the specific assumptions used in a model.

Areas with Higher Direct Risk

In many simulations, states hosting missile silo fields are identified as having the highest potential exposure due to their proximity to strategic targets. These states include:

• Montana

• North Dakota

• Wyoming

• Nebraska

• Colorado

Because these areas contain concentrations of land-based nuclear missiles, simulations suggest that they could experience the most severe immediate effects—including blast damage and high levels of radioactive fallout—if those facilities were struck.

Some models also indicate that neighboring states such as Minnesota, Iowa, and Kansas could receive significant fallout due to prevailing wind patterns that might carry radioactive particles across the Midwest.

The presence of missile silos in the Great Plains and upper Midwest dates back to strategic planning during the Cold War. These regions were selected decades ago because they offered large expanses of land, distance from coastlines, and strategic depth within the continental United States.

Regions Sometimes Modeled with Lower Relative Exposure

In contrast, certain modeling scenarios show comparatively lower radiation exposure in areas located farther from silo fields and fixed strategic missile installations. Parts of the East Coast, the Southeast, and the Northeast are occasionally identified as regions that might experience lower direct fallout levels in average modeling scenarios.

States sometimes included in this category are:

• Maine

• New Hampshire

• Vermont

• Massachusetts

• Rhode Island

• Connecticut

• New York

• New Jersey

• Pennsylvania

• Delaware

• Maryland

• Virginia

• West Virginia

• North Carolina

• South Carolina

• Georgia

• Florida

• Alabama

• Mississippi

• Tennessee

• Kentucky

• Ohio

• Indiana

• Michigan

Some simulations also suggest that sections of the West Coast—including Washington, Oregon, and California—could receive comparatively lower cumulative radiation doses in average-case models due to their distance from central missile fields and typical wind trajectories.

Nevertheless, experts emphasize that even these regions would not be immune to the broader consequences of a nuclear exchange. Fallout drift, infrastructure failures, disruptions to food and energy systems, and environmental contamination could affect areas far removed from the original detonation sites.

Why Geography Matters—but Isn’t the Whole Story

Geographic factors are central to nuclear fallout modeling because they influence how heat, blast energy, and radioactive particles might spread after an explosion. Variables such as wind direction, atmospheric conditions, terrain features, and population density can significantly alter projected outcomes.

However, scientists also stress that geography alone does not determine the impact of a nuclear conflict.