Constructed in July 1863 on a bluff 90 metres above the Waikato River, Alexandra Redoubt is the best preserved of all the forts built at this time. The large redoubt is rectangular, with flanking angles protruding from diagonally opposite corners. The site commands grand views of the broad and lazy river and paved the way for the successful operations of the British River fleet assembled for the Waikato Campaigns.

In September 1863 the nearby army supply depot of Camerontown was attacked and sacked by Ngati Maniapoto. Hearing the firing, a detachment was sent from the fort. In the fighting which ensued, the bravery of Colour-Sergent Edward McKena later earned him the Victoria Cross.

The redoubt is now an historic reserve, and contains a memorial recording the names of the British troops who died in action during the Waikato War.