In this article, a comprehensive analysis of the circumstances surrounding the deaths of all United States presidents who have passed away is presented. Based on historical documents, medical conclusions, and expert assessments, the chronology and causes of death of the presidents of the United States are reconstructed. Special attention is given to eight presidents who died while in office, including four who were killed by assassins and four who died of natural causes. The statistical analysis covers natural mortality, assassinations, diseases concealed from the public, as well as unique historical coincidences related to the dates of the presidents' deaths.