Assigned to the 2nd Division, Asiatic Fleet (formalized as the Yangtze Patrol in 1922), Monocacy sailed upriver from Shanghai on 29 June 1914 to cruise between Ichang and Chungking. For the next 15 years, but for annual visits to Shanghai for overhaul, the gunboat patrolled the upper Yangtze with Chungking her upriver base. Monocacy protected American interests in treaty ports down the entire length of the Yangtze, at times escorting vessels, evacuating American citizens during periods of disturbance, and, in general, assisting U.S. Consulates in various Chinese cities.