Shoreham Redoubt (often referred to as Shoreham Fort) is a defensive structure at the entrance to Shoreham harbour, at the mouth of the River Adur in West Sussex, England. It was planned in the 1850s during a period of political alarm about a possible French invasion, exacerbated by the belief that the Royal Navy was no longer capable of deterring the French following the introduction of iron built, steam powered battleships by the French navy. Construction of the fort was completed in June 1857 at a cost of £11,685. The design is similar to that of Littlehampton Fort, which had been built in 1854.