The military rank of lieutenant in the United States Army, United States Air Force, and United States Marine Corps is now divided between:
During the American Civil War (1861-1865), brevet second lieutenants in the Union Army and Confederate States Army were sometimes also known as "third lieutenants".
In the United States Navy, United States Coast Guard, National Oceanic and Atmospheric Administration Commissioned Officer Corps, and United States Public Health Service Commissioned Corps, the rank of lieutenant is now divided between: