The Trigno (Latin ''Trinius'') is an

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

river. It originates in the

Apennine Mountains The Apennines or Apennine Mountains (; grc-gre, links=no, Ἀπέννινα ὄρη or Ἀπέννινον ὄρος; la, Appenninus or – a singular with plural meaning;''Apenninus'' (Greek or ) has the form of an adjective, which wou ...

, in the

province of Isernia The province of Isernia ( it, provincia di Isernia) is a province in the region of Molise in Italy. The provincial capital is the city Isernia and the president of the province is Alfredo Ricci. The province of Isernia has an area of and a popu ...

and flows into the

Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...

near

Vasto Vasto ( Abruzzese: '; grc, Ἱστόνιον, Histonion}, la, Histonium) is a ''comune'' on the Adriatic coast of the Province of Chieti, in southern Abruzzo, Italy. During the Middle Ages it was called d''Guastaymonis'', '' Vasto d'Aimone'' or ...

. It also forms the border between the

regions In geography, regions, otherwise referred to as zones, lands or territories, are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and t ...

Abruzzo Abruzzo (, , ; nap, label=Neapolitan language, Abruzzese Neapolitan, Abbrùzze , ''Abbrìzze'' or ''Abbrèzze'' ; nap, label=Sabino dialect, Aquilano, Abbrùzzu; #History, historically Abruzzi) is a Regions of Italy, region of Southern Italy wi ...

and

Molise Molise (, , ; nap, label=Neapolitan language, Neapolitan, Mulise) is a Regions of Italy, region of Southern Italy. Until 1963, it formed part of the region of Abruzzi e Molise, alongside the region of Abruzzo. The split, which did not become effe ...

See also