After the war Timothy O’Sullivan often portrayed vast landscapes. From 1867 to 1869 he was the official photographer of Clarence King’s United States Geological Exploration of the 40th Parallel, taking photos of mines and geologic sites, and in 1870 he acted as photographer for a team that went to Panama in search of a canal route. In 1871, 1873, and 1874 he was associated with a series of surveys in the southwestern United States, during which he created powerful, carefully composed images of sweeping landscapes. During this time he also photographed Native Americans whom he met during his travels, portraying them with gravity and a deep sense of respect. On his return east, he was appointed first photographer for the newly established United States Geological Survey, and later, on the recommendations of Brady, King, and Gardner, he was appointed chief photographer for the Department of the Treasury in 1880. Already ill with tuberculosis, he left this position after only a few months because of poor health.