Stowe Castle was built in 1740, two miles east of the gardens, mainly to mask the farm buildings behind. It is now privately owned.  

A small granite obelisk near the Bourbon Tower was put up in 1864 as a memorial to the dissolute 2nd Duke of Buckingham by the Royal Buckinghamshire Yeomanry, who had the misfortune to have him as their Colonel.

The Bourbon Tower earned its name in tribute to a visit by the exiled French royal family, who were based at nearby Aylesbury. The original conical roof was removed in 1843 when the 2nd Duke turned it into a mock fort for exercises.

The Wolfe Obelisk is 100 foot high and was dedicated to General Wolfe, the victor of Quebec in 1759 and a friend of the family. It was placed as the counterpoint to the Cobham Monument.  

The Conduit House supplied water to the main house, as well as acting as a shelter from the rain.