In 1872 Henshaw went to Salt Lake City on the Wheeler Survey as a naturalist, and in 1874 had his most successful field expedition, going from Santa Fe, New Mexico to Gila River and south-western Arizona. There he met with the native Apaches, and caught specimens for the Smithsonian. In 1875, he returned to Washington, and was approached by John Wesley Powell of the Bureau of Ethnology. Along with C. Hart Merriam and Grove Karl Gilbert, Henshaw set out West on the United States Geological Survey, where in addition to his ornithological work, Henshaw worked on linguistics and anthropology, eventually compiling two volume book titled Handbook of North American Indians North of Mexico.