Peace Officers Memorial Day, which honors police officers who died in the line of duty, is Friday, May 15.
Postal Service facilities are required to fly the flag at half-staff. When the U.S. flag is flown at half-staff, all other flags must fly at half-staff, too.
To fly the flag at half-staff, hoist it to the peak of the flagpole for an instant and then lower it to the half-staff position. The flag should be raised to the peak again before it’s lowered for the day.
The USPS Administrative Support Manual has guidelines on U.S. flag display and maintenance.
