The County of Caroni is located on the island of Trinidad, the major island in the Republic of Trinidad and Tobago. It lies south and southwest of the County of St. George , west of the County of Nariva and north of the County of Victoria . To the west it is bounded by the Gulf of Paria. County Caroni includes the town of Chaguanas, the largest town (by population) in the country. Admistratively it is divided between the Borough of Chaguanas, and the Couva-Tabaquite-Talparo and Tunapuna-Piarco Regional Corporations.

County Caroni, which takes its name from the Caroni River , stretches from the hills of the Central Range into the lowlands of the Caroni Plains and the Caroni Swamp. It is heavily associated with sugar cane and the Sugar Belt, but it actually accounts for no more than one third of the sugar belt. The now-defunct state-owned sugar company, Caroni (1975) Ltd took its name from the county.

The major towns of County Caroni are Chaguanas and Couva. The port and industrial zone of Point Lisas is also located in Caroni.

Caroni is often used symbolically to represent the Indo-Trinidadian heartland and the power base of the United National Congress.