Simon II de Clermont, Lord of Nesle, Lord of Ailly, was born 1208 to Raoul I de Clermont (1185-1214) and Gertrude de Nesle-Falvy (c1177-c1224) and died 1 February 1280 of unspecified causes. He married Adela de Montfort (1230-1279) 1242 JL .
Children
| Name | Birth | Death | Joined with |
| Raoul II de Clermont (1245-1302) | 1245 | 8 July 1302 Kortrijk | Alix de Dreux (1254-1296) |
| Béatrice de Clermont-en-Beauvaisis | |||
| Ide de Clermont (1251-c1298) | 1251 | 1298 | Robert VII Bertrand de Bricquebec (1252-1308) |
| Guy I de Clermont (1255-1302) | 1255 | 8 July 1302 Kortrijk | Marguerite de Thourotte |
Footnotes (including sources)
| ‡ General |