Lewis Tower, Jersey, Martello tower in St Ouen's Bay, Jersey

Lewis Tower is a Martello tower built in 1835 in St Ouen's Bay. It has an elliptical footprint, stands 33 feet high with a diameter of 39 feet, and its wall is thicker on the seaward side. Inside, three levels are linked by a circular spiral staircase around a central pillar. It was armed with a single 24-pounder gun.

A battery of three 24-pounder guns was placed on this spot in 1787, and the tower itself was built in 1835 and named after Colonel Griffith Lewis, who commanded the Royal Engineers in Jersey from December 1830 to January 1836. The site had already seen action on 1 May 1779, when the Rector of St Ouen brought parish field guns here during the Franco-Dutch invasion. Four years after completion the tower was coated in stucco to reduce damp.

The tower takes its name from Colonel Griffith Lewis, who commanded the Royal Engineers in Jersey from December 1830 to January 1836. Its site had earlier military use: in 1779 the Rector of St Ouen, le Sire du Parcq, brought parish field guns there to help repulse the Franco-Dutch invasion, and in 1787 the British placed a battery of three 24-pounder guns on the spot.

The tower accommodates about six people with electricity and camp beds available, though visitors need to bring sleeping bags and food supplies. Access is best made on foot across the beach, and tidal conditions should be checked before visiting.

During World War II, German forces constructed a concrete extension at the tower's base for a searchlight facility and built an adjacent military bunker. These additions remain visible today and demonstrate how the site served different purposes across distinct historical periods.