It depends on the year. In the CDC’s 2022 age-adjusted data, **Montana** had the highest suicide rate, about **28.7 deaths per 100,000 people**; **Wyoming** ranked highest in 2021.
Researchers do not identify one cause. They point to a combination of:
- widespread access to firearms, making attempts more likely to be fatal;
- rural isolation and long distances to mental-health care;
- shortages of behavioral-health professionals;
- economic stress, substance use, and social disconnection;
- stigma and a culture of self-reliance that may discourage seeking help;
- disproportionately high risk among some groups, including American Indian/Alaska Native communities and veterans.
High altitude has also been studied as a possible contributor in Mountain West states, but the evidence is correlational and it is not considered a stand-alone explanation.