Thomas Brennan Nolan (May 21, 1901 – August 2, 1992) was an American geologist who was director of the United States Geological Survey (USGS) from 1956 to 1965.

Nolan believed that geologists, because of the unique requirements imposed on them by their science, should expand their fields of interest from individual problems and "participate actively and authoritatively in the matters affecting the whole country."

In 1956, the Geological Survey began an evaluation of the effects of underground nuclear explosions at the Atomic Energy Commission's Nevada Test Site; that program was expanded to study the geologic and hydrologic conditions affecting the peaceful uses of atomic energy and the disposal of radioactive wastes.

In December 1958, Director Nolan, speaking at the meeting of the American Association for the Advancement of Science, remarked that the early work of the Geological Survey had been characterized by a transition from exploration of a geographical to an intellectual frontier, but demands by younger scientists for studies of the geography of outer space might soon inaugurate a new cycle in the history of the US Geological Survey.

In 1959, the Survey compiled a photogeologic map of the Earth's satellite, the Moon, and began studies of tektites and impact craters.