The United States Exploring Expedition, 1838-1842

"Andes near Alparmarca, Peru: Sketched from an Elevation of 16,000 Feet". Illustration by Alfred Thomas Agate from the South American portion of the United States Exploring Expedition, digitally restored.

U.S. Navy Lieutenant Charles Wilkes and his small fleet of ships carried out the most comprehensive American scientific mission since the Lewis and Clark expedition.

What was officially called the United States South Seas Exploring Expedition set sail from Norfolk, Virginia, on August 18, 1838. It consisted of six ships under the command of Lt. Charles Wilkes, only forty years old but already claiming twenty years experience in the Navy. The Expedition had been authorized by Congress ten years earlier by a resolution “that one of our small public vessels be sent to the Pacific ocean and South sea, to examine the coasts, islands, harbors, shoals, and reefs in those seas, and to ascertain their true situation and description.”

The Naval and Civilian Crews of the Expedition

The six ships, in addition to their nearly 500 naval personnel, carried nine civilian scientists: two naturalists, two botanists, two artists, a mineralogist, a philologist, and a conchologist. These nine men, called the scientific corps, or simply the “scientifics,” went on to become major contributors in their respective fields and authored most of the 19 volumes of the Expedition’s final report. One of them, the mineralogist James Dwight Dana, authored two college textbooks, revised editions of which are still in use today.

Some Highlights of the Expedition

Over the course of its four-year voyage, the Expedition conducted significant explorations in, and amassed extensive collections of flora, fauna, and artifacts from, locations around the Pacific rim.

  • Tierra del Fuego – Used as a base from which to explore the seas to the south.
  • Antarctica – Surveyed 1500 miles of coastline, establishing Antarctica as a continent.
  • Tahiti, Samoa, and Fiji – Collected thousands of natural specimens, including coral.
  • Sandwich Islands (Hawaii) – Studied volcanism and climbed to the summit of Mauna Loa.
  • Oregon – Mapped the coast and interior, helping to establish American claims to the area.

The Expedition and the Smithsonian Institution

The Expedition brought back an astonishing variety of objects: 2,000 birds; 150 mammals; 1,000 corals, crustaceans, and mollusks; 50,000 plants; many hundreds of rocks, minerals, and fossils; and over 5,000 human artifacts. Today many of these objects can be seen at the Smithsonian Institution’s Natural History Museum; but at the time, Joseph Henry, the head of the Smithsonian, didn’t want them. The Institution was established four years after the Expedition’s return, and Henry did not intend for it to be a museum at all; he believed it should be purely a research institution. However, the specimens and artifacts had to be housed somewhere; and eventually Henry agreed to take them.

The Exploring Expedition of 1838-42 was the largest and most successful American scientific endeavor since Lewis and Clark had made their way to the Pacific and back a generation before. It would be followed by numerous similar, if smaller, expeditions throughout the 1840s and ‘50s. Its collections would become the core of what is now the Smithsonian Institution’s National Museum of Natural History.


  1. Viola, Herman J. and Margolis, Carolyn, eds. Magnificent Voyagers. Washington: Smithsonian Institution Press, 1985, 7.