Vermandois was a French county, that appears in the Merovingian period. In the 10th century, it was organised around two castellan domains: St Quentin (Aisne) and Péronne (Somme). In today's times, the Vermandois county would fall in the Picardy region of northern France.

Vermandois was a French county, that appears in the Merovingian period. In the 10th century, it was organised around two castellan domains: St Quentin (Aisne) and Péronne (Somme). In today's times, the Vermandois county would fall in the Picardy region of northern France.