Herculaneum is a city in Jefferson County, Missouri, United States. The population was 3,468 at the 2010 census. The City of Herculaneum was the first county seat of Jefferson County from January 1, 1819 to 1839. The city celebrated its bicentennial throughout 2008.
The city received the "Tree City USA" designation by the Arbor Day Foundation for 11 consecutive years, 2007 through 2017. The city is the honorary hometown of the 40th Airlift Squadron, "The Screaming Eagles," from Dyess Air Force Base in Texas.
Herculaneum is located at 38°15′33″N 90°23′16″W (38.259247, -90.387790).
According to the United States Census Bureau, the city has a total area of 4.10 square miles (10.62 km2), of which 4.06 square miles (10.52 km2) is land and 0.04 square miles (0.10 km2) is water.
Herculaneum was laid out by Moses Austin and Samuel Hammond in 1808 as a shipping point on the Mississippi River closer to Austin's lead mines in Potosi than was Ste. Genevieve.
The town was named after the ancient Roman town of Herculaneum, destroyed by the eruption of Mount Vesuvius. Austin is said to have chosen the name because the limestone ledges overlooking the Mississippi River resembled a Roman amphitheatre.