After the emperor's second abdication he was banished from France and, refusing an offer for employment from czar
Alexander I of Russia, emigrated to the United States, where he was accepted as an assistant engineer with the rank and pay of a brigadier-general of engineers on November 16, 1816. He designed a number of extensive forts for the Army, notably
Fort Monroe and
Fort Wool in Virginia,
Fort Adams in
Newport, Rhode Island,
Fort Morgan in Alabama,
Fort McRee in Florida and
Fort Pulaski in Georgia. During
Marquis de LaFayette's famous
trip to the United States in 1824–1825, the Marquis admired Fort Monroe, the
Old Point Comfort stronghold which had also been designed by Bernard. During his time in America, he was a member of the prestigious
Columbian Institute for the Promotion of Arts and Sciences, which counted among its members presidents
Andrew Jackson and
John Quincy Adams and many prominent men of the day, including well-known representatives of the military, government service, medical and other professions. In 1829, under the employ of the U.S. congress, Bernard completed a survey to discover the feasibility of a
Cross Florida Canal. He resigned from the United States Army on August 10, 1831. ==Return to France==