Alfred d'Orsay (1801-1852), comte d'Orsay, had no children so I believed that the title passed to his sister Ida d'Orsay (who is mentioned to be countess of Orsay on various websites) and then to her
eldest son Agénor de Gramont (1819-1880) (10th duke of Gramont) only still living child Antonia Gabrielle Léontine.
However, there are two issues here:
AgénorAntonia never used the title "compte d'Orsay" as far as I know,
- the title was never claimed again.
So who was the last count of Orsay, and who is the last person we have trace of who could claim it?