Elizabeth Hay, Countess of Erroll (née FitzClarence; 17 January 1801 – 16 January 1856) was an illegitimate daughter of King William IV of the United Kingdom and Dorothea Jordan.

[3] Elizabeth and William Hay married at St George's, Hanover Square.

[4][5] Hay is pictured in a FitzClarence family portrait in House of Dun, and kept a stone thrown at her father William IV and the gloves he wore on opening his first Parliament as mementos.

[6] In 1856, while ill herself, she was summoned from Scotland to visit her dying brother Adolphus.

Her illness worsened and she died on the journey in Edinburgh, Scotland.