Robert Mills (1781-1855) was the first native-born architect to be trained in America. Born in Charleston, S.C., Mills was educated at the College of Charleston and then studied architecture under James Hoban, the architect of the White House. Thomas Jefferson counseled the young man and provided him with access to his great architectural library. In 1808 he began working with Benjamin Latrobe, who impressed upon Mills his devotion to classic Greek design, principles of professional practice and science-based engineering.

After opening his own professional office, Robert Mills designed some of America's premier architectural creations. His work included houses, churches, college buildings, bridges, hospitals and government offices. He is best remembered as the designer of the Washington Monument, the U.S. Patent Office, the old Post Office in Washington, and the U.S. Treasury Building.
In 1830 he was appointed by President Andrew Jackson to the newly-created position of "Architect and Engineer" to the Federal Government. He maintained this position until his death in 1855.

During his tenure he designed ten marine hospitals for the government. In 1837 he prepared two different designs. The larger building, to house and care for 100 boatmen, was selected for this site in Louisville. A smaller version, housing fifty patients, was built downriver in Paducah, Kentucky. Of the 10 inland marine hospitals designed by Robert Mills, the Louisville facility is the only building still standing.

In addition to his creation of the Louisville United States Marine Hospital, Robert Mills had another connection to this community. His youngest daughter, Anna T. Mills, married Fortunatus Cosby, Jr. in 1854. Cosby was the son of a noted local judge, one of the original owners of the land that would become Portland.