Operation Sahayogi Haat was a US military relief operation delivering humanitarian assistance to victims of the April and May 2015 Nepal earthquakes. About 900 US military and civilian personnel were involved, with about 300 deployed in Nepal. 3rd Marine Expeditionary Brigade was tasked to form Joint Task Force 505, which was responsible for managing the relief operation from May 6 to 26, 2015.

A major earthquake occurred in Nepal on 12 May 2015 at 12:50 pm local time with a moment magnitude of 7.3, 18 kilometres (11 mi) southeast of Kodari. The epicenter was on the border of Dolakha and Sindhupalchowk, two districts of Nepal. This earthquake occurred on the same fault as the larger magnitude 7.8 earthquake of 25 April, but further east than the original quake. As such, it is considered to be an aftershock of the April quake. It struck at a depth of 18.5 km (11.5 mi). Shaking was felt in northern parts of India including Bihar, Uttar Pradesh and West Bengal. Tremors were felt as far as about 2,400 km away from the epicenter in Chennai.