The original Royal Sussex Regimental Museum was established in 1930 at the Regimental Depot in Chichester. With only basic resources available the exhibits were laid out on tables. The museum was intended to be a resource for the benefit of recruits and members of the regiment.

The outbreak of the Second World War led to the closure of the museum with all the items being placed into store. In 1948 the official reopening of the museum coincided with the amalgamation of the 1st and 2nd Battalions, and of the 4th and 5th Cinque Ports. The following 12 years saw the addition of many important items to the collection including the purchase of Sergeant Harry Wells’ Victoria Cross.

The Regimental Depot closed on 31 March, 1960 but a Trust was started for the care of the museum. In 1962 the museum was again placed into store although two rooms were set aside in the new Chichester Museum for a display.

In 1977 the Regimental Headquarters closed and the collections were moved to the Redoubt Fortress in Eastbourne. To this day The Royal Sussex Regimental Museum Trust and The Royal Sussex Regimental Association continues to work with the Redoubt to ensure the quality of both the Fortress and its collection are of the highest standard.