Financial concerns obligated him to terminate his gymnasium studies in Bonn prematurely. He worked some at agriculture in Pomerania, then went (1850) to North America, joining (1851) Duke Paul of Würtemberg and his party in the Rocky Mountains. He was wounded by Indians but, after five months, navigated the Mississippi River to New Orleans.
Back in Berlin in early 1853, he met Alexander von Humboldt and became his house guest. At the instigation of Humboldt, he became topographer and draughtsman for a scientific expedition to the far west of the United States under Lieutenant Amiel W. Whipple, departing May 1853, and returning in 1854, via San Francisco and the Isthmus of Panama, to Germany, where he was appointed custodian of libraries in Potsdam by Frederick William IV of Prussia at the urging of Humboldt. On February 6, 1855, he married Carolina Alexandra Seifert, Humboldt's ward, who he had met while living in Humboldt's household.
He made another trip (1857–58) to North America accompanying an expedition under Lieutenant Joseph C. Ives exploring central Colorado and the Colorado River. His remaining years were spent mostly at home writing, which his position as library custodian provided the leisure for.
- Tagebuch einer Reise vom Mississippi nach den Küsten der Südsee (“Diary of a trip along the Mississippi to the Gulf”; Leipzig, 1858; English translation by Mrs. Sinnett, 2 vols., London, 1858; 2d ed., entitled Wanderungen durch die Prairien und Wüsten des westlichen Nordamerika, 1860)
- Reisen in die Felsengebirge Nordamerikas bis zum Hochplateau von Neu-Mexiko (“Traveling in the Rocky Mountains of North America up to the high plateau of New Mexico”; 2 vols., Leipzig, 1861)
- Die Halbindianer (“The Halfbreeds”; 1861)
- Der Flüchtling: Erzählung aus Neu-Mexiko (“The Refugee: A tale from New Mexico”; 1862)
- Palmblätter und Schneeflocken: Erzählung aus dem fernen Westen (“Palm leaves and snowflakes: A tale from the far west”; 2 vols., 1863)
- Der Mayordomo: Erzählung aus dem südl. Californien und Neu-Mexiko (“The majordomo: A tale from Southern California and New Mexico”; 4 vols., 1863)
- Das Mormonenmädchen (“The Mormon maiden”; 6 vols., 1864; 3d ed., 1871)
- Reliquien: Erzählung aus dem westlichen Nordamerika (“Relics: A tale from the west of North America”; 3 vols., Berlin, 1865)
- Die Mandanenwaise: Erzählung aus den Rheinlanden und dem Stromgebiet des Missouri (“The Mandan orphan: A tale from the Rhinelands and the Missouri River Valley”; 4 vols., 1865);
- Nord und Süd: Erzählungen und Schilderungen aus dem westlichen Nordamerika (“North and South: Tales and depictions from the west of North America”; 2 vols., Jena, 1867)
- Das Monogramm (1874)
- Die beiden Yachten (“The two yachts”; 1891)
- Der Spion (“The Spy”; 1893)
- Das Fegefeuer in Frappes Wigwam (“Purgatory in Frappe's Wigwam”; 1900)
A collection of his works was published (1906–13), under title of Illustrierte Romane, Reisen und Abenteuer (“Illustrated novels, travels and adventure”).
- Wilson, James Grant; Fiske, John, eds. (1900). "Möllhausen, Balduin". Appletons' Cyclopædia of American Biography. New York: D. Appleton.
- "Möllhausen, Balduin". New International Encyclopedia. 1905.
- "Möllhausen, Balduin". The American Cyclopædia. 1879.
- This article incorporates text from a publication now in the public domain: Rines, George Edwin, ed. (1920). "Möllhausen, Baldwin". Encyclopedia Americana.
- Ben W. Huseman (1995). Wild river, timeless canyons. Balduin Möllhausen's watercolors of the Colorado. Fort Worth, Texas: Amon Carter Museum. ISBN 0-88360-084-6