As Paul states this is a bit of an oddity. It is already inscribed as one of the "Associated sites" of the James Island WHS.

It is located in Barra, which sits opposite the capital Banjul and is connected by a very busy ferry route. The fort is located a short distance from the ferry port but the road is quite poor and very sandy so it is tough to get nearby motorised transport, so it is probably best to approach on foot is you have a wait for the ferry. There is not a huge amount to see at the fort just the old walls and a few scattered cannon.

This actually is really good addition to the James Island site. It transforms this from being just a holding pen for slaves into one that shows the evolution of the Slave Trade and also the battle to control and eradicate it. Fort Bullen was built in 1827 at a similar time to the six gun battery in Banjul. This enabled the British to control ships coming in and out of the River Gambia and help to enforce the abolition of the slave trade. Whilst Fort Bullen is not a massively impressive site its incorporation into the Wider James Island WHS helps to illustrate the evolution of slavery on the River Gambia.