Louisa married William Brabazon Ponsonby, 1st. Baron Ponsonby of Imokilly on 26 Dec 1769. William (son of Rt. Hon. John Ponsonby and Lady Elizabeth Cavendish) was born on 15 Sep 1744; died on 5 Nov 1806 in London, England; was buried in Ireland. [Group Sheet]

1. John Brabazon Ponsonby, Viscount Ponsonby was born about 1770; died on 21 Feb 1855 in Brighton, Sussex, England.
2. Major-General Sir William Ponsonby, KCB was born on 13 Oct 1772; died on 18 Jun 1815 in Waterloo, Belgium.
3. Richard Ponsonby was born in 1772 in Dublin, Ireland; died in 1853.
4. George Ponsonby was born about 1774; died on 5 Jun 1863 in Midhurst District, Sussex, England.
5. Frederick Ponsonby was born in Unknown; died in 1849; was buried in Oughterard, Kildare, Ireland.
6. Mary Elizabeth Ponsonby was born on 3 Mar 1775; died on 26 Nov 1861 in St. George's, Hanover Sq. Middlesex, England; was buried in St. Michael & All Angels, Alnwick, Northumberland, England.

Louisa married William Fitzwilliam, 4th. Earl Fitzwilliam on 21 Jul 1823 in Bishopscourt, County Kildare, Ireland. William (son of William Fitzwilliam, 3rd. Earl Fitzwilliam and Lady Ann Watson-Wentworth) was born on 30 May 1748 in Milton House, Peterborough, Northamptonshire, England; died on 8 Feb 1833 in Milton House, Peterborough, Northamptonshire, England; was buried on 24 Feb 1833 in Marholm, Northamptonshire, England. [Group Sheet]