Fort Dette is a Civil War earthwork fortification built by Union forces in 1861 to protect Rolla's crucial rail supply lines. The fort takes its name from Lieutenant Colonel Joseph B. Plummer, and is sometimes called Star Fort for its distinctive Greek Cross configuration — a shape designed to allow defenders to fire in any direction without exposing themselves.
The earthworks are still partially visible in the landscape on the north side of Rolla. They are not heavily interpreted and require some imagination, but Civil War enthusiasts will appreciate the connection to Rolla's role as a Union logistics hub — the town was where General Frémont staged much of his western campaign.