Minchendon House was in Enfield, near (and now within) London. 

The house was built around 1747 by John Nichol. His widow, Margaret, married James Brydges, 3rd Duke of Chandos, father of the first Duchess. His second wife, the Duchess Dowager of Chandos, lived at Michenden during her insanity. Mary Buchanan also lived there for a short while, as did Richard Gamon until his death. It was also home to the Misses Williamson. 

On the death of the Duchess in January 1813, the house passed to the Buckinghams. From 1822, they unsuccessfully tried to the let the property. By 1827, the house and grounds were decaying:

When I was at Minchenden Bason requested me to state to your Grace that the Kitchen Garden was not in Cultivation & that He had neither the means to cultivate or manure […] Bason has been affected with gout &c. for the last month & is still incapable of business consequently your Grace’s Beautiful Villa is in a most deplorable state... If you sell [the manor of Hollick] I should propose laying the purchase money out in the most necessary repairs at Minchenden House &c. &c. (Thomas Crawfurd to Anna Eliza Brydges. HEH STG Correspondence Box 363 (30); 1827/10/07)

In 1828, interest was expressed in renting the house:

I have this day a Note from Lady Nugent requesting the particulars for Letting Minchenden House & Garden. I have answered by stating that the Letting of Minchenden House and Garden was not thought of when I left Southgate and that I found it necessary to consult your Grace. (Thomas Crawfurd to Anna Eliza Brydges. HEH STG Correspondence Box 363 (52); 1828/08/28)

Lady Nugent did not rent the house and in October and November 1828, the house was advertised for rent. 

If Minchenden is not Let by the 6th of October I wish to be informed if your Grace pleases to advertise it again. (Thomas Crawfurd to Anna Eliza Brydges. HEH STG Correspondence Box 363 (54); 1828/09/26)

I have again advertised Minchenden House to be let in the Morning Chronicle & Courier Newspapers. (Thomas Crawfurd to Anna Eliza Brydges. HEH STG Correspondence Box 363 (55); 1828/11/03)

The house was not let. In 1832, Sir Edward East was intending to spend the summer there; he noted that the House cost £3,000 a year to run and suggested it as a home for the first Duchess (HEH STG Correspondence Box 6 (22); 1832/04/26). The house and grounds had improved when Richard Temple visited in 1833:

I returned last night from my [?] Holidays. Minchenden looked very nice. The opening of the great Cedar by throwing down the Wall is a great improvement. The Yew Hedge remains untouched. [More on the Garden…] (Temple to Anna Eliza Brydges. HEH STG Correspondence Box 7 (30); undated. 1833?)

Before the end of 1836, Minchenden House was sold Isaac Walter for £13,800 (Beckett, page 197). A painting of Minchenden was sold at the 1848 sale, the catalogue entry giving the date of sale as 1829.

The house was demolished in 1853 and the ground are now Minchenden Oak Gardens.