Sant'Elia a Pianisi is a comune (municipality) in the Province of Campobasso in the Italian region Molise, located about 20 kilometres (12 mi) northeast of Campobasso. As of 31 December 2004, it had a population of 2,178 and an area of 67.8 square kilometres (26.2 sq mi).Sant'Elia a Pianisi borders the following municipalities: Bonefro, Carlantino, Colletorto, Macchia Valfortore, Monacilioni, Ripabottoni, San Giuliano di Puglia.
Near Sant'Elia are the ruins of the mediaeval Castello di Pianisi, first mentioned in documents of the second half of the thirteenth century. It is not known how or when the castle was destroyed.: 433
Sant'Elia a Pianisi is served by a railway station, the Ripabottoni-S:Elia railway station, on the Termoli-Campobasso and Termoli–Venafro line.