The rank of 1st Lieutenant belongs to which officer grade in the Marine Corps?

The rank of 1st Lieutenant in the Marine Corps corresponds to the officer grade O-2. In the military ranking system, the letter "O" signifies an officer rank, and the number indicates the specific grade level. 1st Lieutenant is classified as O-2, which comes after the rank of Second Lieutenant (O-1) and before Captain (O-3).

This hierarchical structure is important for understanding the responsibilities, authority, and progression of ranks within the Marine Corps and other branches of the armed forces. Recognizing these designations aids in distinguishing between various levels of commission and the corresponding leadership roles they encompass.