Lamu Fort, Military fortress in Lamu old town, Kenya.

Lamu Fort is a massive two-story stone building at the southeast corner of Lamu's old stone town, about 70 metres from the main jetty. It was built beside the 14th-century Pwani Mosque, and its squat, powerful form contrasts with the town's Swahili architecture. Thomas Boteler in 1823 described a large square building with a tower at each corner and a vaulted entrance.

Omani Arabs built the fort between 1813 and 1821 to secure Lamu's harbor after the Battle of Shela. It later served as a prison during British colonial rule, a function that continued until the 1980s.

The fort shows arched openings and coral stone details that are typical of Swahili coast buildings, mixing Arabic and Indian touches. These elements appear throughout Lamu town as well, making the fort a good starting point for reading the local architecture.

The fort stands about 70 metres from the main jetty, in the centre of the old town rather than on the waterfront. Its ramparts give views over Lamu town. The ground floor holds the museum, while offices, laboratories and a workshop occupy the second floor.

Although built as a military defense, the fort now houses an environmental museum and a library run by the National Museums of Kenya. Its large inner courtyard is regularly used for weddings and public performances by local residents.