Chieti is the most eastern province in Abruzzo and has an area of , the second largest province in the region after the province of L'Aquila. The province is bordered to the north and east by the Adriatic Sea, to the northwest by the province of Pescara, to the southwest by the province of L'Aquila and to south and southeast with Molise (to the south with the province of Isernia and to the southeast with the province of Campobasso).