Fort Paull is technically a defended battery rather than a fort and served for many centuries to defend the Humber approach to Hull. The earliest battery dates from around 1542, in the reign of Henry VIII. Various extensions and improvements were made over the years and the current structure dates from the 1860s. Its final armamemnt comprised two 4.7 inch guns and three six inch pieces. In 1915 the guns were removed and the site served as a Headquarters for Fire Control.
Within the fort are protected gun emplacements linked by tunnels and a small underground medical facility. The two magazines were built in 1864. A small concrete observation post dating from 1886 also exists, built into the ramparts to control a submarine mining installation. The south eastern magazine has a later observation post atop and the north western magazine housed a generator for searchlights which illuminated the Humber. During World War II, the site was used for ammunition storage.
After closure in 1960, the site was bought and converted to a museum which closed at the end of 2019. The contents of the site were auctioned in 2020, including the only surviving Blackburn Beverley Transport Plane. The whole site is a scheduled monument.