 Lord Nelson was married on 28 July 1845 at St George's Church, Hanover Square, to Lady Mary Jane Diana Agar, daughter of The 2nd Earl of Normanton and granddaughter of The 11th Earl of Pembroke.She died in 1904.They had several children, including Herbert Horatio, styled Viscount Trafalgar, who died in 1905, Thomas Horatio, who succeeded his father as 4th Earl Nelson, and Edward Agar Horatio, who eventually succeeded as fifth Earl in 1947.