The US Secret Service said a bullet hit an exterior window of the White House and was stopped by ballistic glass.
An additional round of ammunition was also found on the exterior of the White House. The bullets were found yesterday.
The discovery follows reports of gunfire near the White House on Friday. Witnesses heard shots and saw two speeding vehicles in the area. An AK-47 rifle was also recovered.
The Secret Service said it has not conclusively connected Friday's incident with the bullets found on the White House grounds.
US Park Police have an arrest warrant out for Oscar Ortega-Hernandez, who is believed to be connected to the earlier incident.