Procedures for when the U.S. flag is lowered to half-staff were first spelled out in a proclamation by President Dwight D. Eisenhower on March 1, 1954. Before then, no set regulations on when to lower the flag existed. According to the U.S. Department of Veterans Affairs, flags should fly at half-staff at all federal buildings and grounds and on naval vessels within the United States and its territories.

The length of time the flag is flown at half-staff for the death of a public official differs depending on the prominence of the office: