Elizabeth Forbes was youngest of three children of James Forbes of Seaton and Margaret Gordon. She married Lord James Hay in 1813. Two years later her husband was present at the Battle of Waterloo. The couple had four children, of whom three survived to adulthood; Margueritte, Georgiana and James.

Her father died in 1829, by which time her two older brothers had died childless. She inherited the estate of Seaton.

Lord and Lady Hay travelled extensively throughout Europe between 1830 and 1861. Their correspondence is in the University of Aberdeen's archives.

Lady Hay died in 1861.