Gissi is a town and comune located in the Province of Chieti, Abruzzo, Italy. It is bordered by two tributaries of the Sinello River and is surro…Gissi is a town and comune located in the Province of Chieti, Abruzzo, Italy. It is bordered by two tributaries of the Sinello River and is surrounded by vineyards and olive groves. Gissi has been populated since prehistoric times. In the 12th century it was under the influence of the D'Avalos family.