Prior to his death, the 3rd Duke, Lord Egerton's predecessor, had begun to demolish the medieval Ashridge Priory in order to build a new country house.

[3] Charlotte laid the foundation stone for the new house on 25 October 1808, the 48th anniversary of the accession of George III of Great Britain.

[5] Ashridge House is highly regarded today as one of the finest examples of early Gothic Revival architecture and is now a Grade I listed building.

Repton presented many ideas in his Red Book for the estate in 1813, including a rosarie (or rosarium) and a "Monks' Garden" commemorating Ashridge's monastic heritage with a layout of grave-shaped flower beds.

[12] In addition to Ashridge, Lady Bridgewater and her husband also owned a London property at 7 Grosvenor Square, which they renovated with the assistance of Wyatville.

Sir Jeffry Wyattville, the architect who completed Ashridge House, was again appointed, and in response to the countess's objections, he designed the monumnent as a Neoclassical Doric column.

[25][26] Charlotte exhibited concern for the poor; agricultural workers on the Bridgewater lands had been made destitute during the winter months were unable to feed themselves and their families, and sometime around 1841 the Countess established a soup kitchen within the ruins of Berkhamsted Castle.

[27] Contemporary accounts in the Bucks Herald describe the distribution of soup and bread to hundreds of poor people from a house in the castle grounds, thought to be the 19th-century keeper's lodge which still stands today.

[24] In 1842, she purchased a mansion in Berkhamsted, Egerton House, and donated part of the land to the nearby Parish Church of St Peter for use as a detached cemetery.

[30] A foundation stone in Rectory Lane Cemetery commemorates the donation of the Countess and the consecration of the burial ground by John Kaye, Bishop of Lincoln, on 11 October 1842.

[26][31][32] In 1844, the Countess funded the construction of a chapel of ease in the village of Caldwell, North Yorkshire, on Bridgewater Estate lands.

Her published obituary in The Gentleman's Magazine stated that "She was a very pious and benevolent person, and many recipients of her charity will have to bewail her loss.

A marble wall monument designed by Richard Westmacott commemorates the 7th Earl and a dedication to the Countess:[35][36] "And also to the memory of Charlotte Catherine Anne, widow of John William, Earl of Bridgewater, Born November 20th 1763, died February 11th 1840.Her anxious desire during the 26 years she survived her beloved husband, was to fulfil his wishes, and to carry out his charitable intentions.

A pencil and chalk portrait of the Countess standing in a landscape with her dog was drawn by Henry Edridge in around 1805 and is now in the National Trust's collection at Tatton Hall, Cheshire.