Ille-sur-Tet (catalan: Illa or Illa de Tet) is a French commune, situated in the department of Pyrénées-Orientales and the region Languedoc-Roussillon.
It's inhabitants are called Illois.
The commune is situated on the Riberole along the National 161 and is crossed by the Têt River (in the North), as well as by its tributary, the Boulès (in the South). It is one of the entryways into the Fenouillèdes region (towards Montalba-le-Château or Bélesta).