It was erected by the British in 1835, and is named after Colonel Griffith Lewis, who commanded the Royal Engineers in Jersey from December 1830 to January 1836.
On 1 May 1779, the Rector of St Ouen, le Sire du Parcq, brought the parish field guns to a favourable spot to help repulse the Franco-Dutch Invasion of Jersey.
Four years after Lewis Tower's completion, it received a coat of stucco or cement to reduce the damp.
The bunker today houses the Channel Islands Military Museum.
The Germans also built a concrete extension at the tower's base that housed a searchlight.