S.D. Codified Laws § 1-12-1
There is hereby created a State Constabulary which shall consist of the agents of the Division of Criminal Investigation of the attorney general's office, the agents of the Division of the Highway Patrol, the state conservation officers, the sheriffs, deputy sheriffs, and constables of the several counties of this state, and the police officers, constables, and marshals of the several municipalities within the state. Such State Constabulary, and its personnel, when convoked as hereinafter provided, shall, and is hereby empowered, to perform all of the duties and they shall have the same powers, now devolving upon the agents of the Division of Criminal Investigation of the attorney general's office, and in addition thereto shall have such powers and perform such duties, as may be necessary to preserve and protect the peace, security, safety, and welfare of the state and the people thereof.
SDCL 1-12-1