Plaquemine is noted for a number of antebellum structures that survive within the city limits and along Bayou Road. One of the most noteworthy homes is St. Basil's, a riverfront mansion built by socialite physician Dr. John Scratchley in the 1850s. Now a private residence, the home retains the name St. Basil's from when it was a fashionable convent school.
The Iberville Museum was built in 1949 as the Iberville Parish Courthouse. The building served as Plaquemine's first city hall, and was the city seat of government until 1985. It now serves as a parish museum, and the building is on the National Register of Historic Places.