10 U.S.C. § 8111

The commissioned grades in the Navy above the grade of chief warrant officer, W–5, are the following: (1) Admiral. (2) Vice admiral. (3) Rear admiral. (4) Rear admiral (lower half). (5) Captain. (6) Commander. (7) Lieutenant commander. (8) Lieutenant. (9) Lieutenant (junior grade). (10) Ensign.