United States Army Criminal Investigation Division

The United States Department of the Army Criminal Investigation Division (CID or DACID), previously known as the United States Army Criminal Investigation Command (USACIDC), is the primary federal law enforcement agency of the United States Department of the Army. Its primary function is to investigate felony crimes and serious violations of military law and the United States Code within the US Army. The division is an independent federal law enforcement agency with investigative autonomy; CID special agents, both military and civilian, report through the CID chain of command to the CID Director, who reports directly to the Under Secretary of the Army and the Secretary of the Army. Unlike their counterparts at OSI and NCIS, Army CID does not have primary counterintelligence responsibilities, as this jurisdiction resides with United States Army Counterintelligence Command (ACI).

USACIDC was established as a United States Army command in 1971 and is headquartered at Marine Corps Base, Quantico, Virginia. Worldwide, the organization has slightly fewer than 3,000 soldiers and civilians, of whom approximately 900 are special agents. The initialism "USACIDC" was used to refer to the Army command itself, while criminal investigation personnel and operations are commonly referred to using the shortened initialism "CID", which has its history in the original Criminal Investigation Division formed during World War I. The name restoration to Criminal Investigation Division became official after 2021 reform.