There is no single authoritative reference detailing those provisions of AP I the US accepts as an accurate restatement of customary international law or other legal obligations, or that it follows as a matter of policy during armed conflict. This paper seeks to partially address that lacuna through a systematic review of official US policies, directives, publications, treaty obligations, laws, and proclamations pertinent to those provisions of AP I governing the conduct of hostilities. This paper will not opine whether any of these official materials are conclusive proof that the US accepts any specific provision of AP I as customary international law. Nor will it evaluate the merits of the US position with regard to the instrument. Rather, it will furnish a consolidated resource for the researcher who contemplates these questions. More practically, it will provide military operational law practitioners with US references that embrace, modify, or contradict provisions of AP I as they pertain to the conduct of hostilities.