Idukki district was formed as per Government notification on 24th January 1972. The district consists of Devikulam, Udumbanchola and Peermedu taluks of the former Kottayam district and Thodupuzha taluk excluding two villages Manjallore and Kalloorkadu of the former Ernakulam district. At the time of formation the district headquarters started functioning at Kottayam. It was later shifted to Painavu in Thodupuzha taluk in June 1976, where it is proposed to build a new planned forest township.

The name of the village 'Idukki' is originally derived from a Malayalam word 'Idukku' which means a narrow ravine. Periyar, which is one of the largest rivers of Kerala, flowing through Idukki gorge formed between the two high massive rocks called 'Kuravan' and 'Kurathi', is the site of the gigantic Idukki arch dam.

Very little can be known as the past that throws light into the ancient history of Idukki district. There is no clear evidence whether men of the paleolithic age lived here or not; but stone-age civilization is present here. Stone-age dolmens were discovered in the valleys of Anchanad in Devikulam taluk. Archaeological digging conducted during 1947-48 at Kallar Pattom colony in Udumbanchola taluk and at Vandiperiyar in Peermedu taluk brought to light the remains of Old Stone-age Menhir and Tombs.

The head quarters of Vadakkumkoor Raja was Karikode near Thodupuzha. There are remains of a fort at Karikkode near which there is a Devi temple said to have constructed by the Vadakkumkoor Raja. There is also another temple known as Annamala Temple constructed in Chola style. The church at Muthalakodam, near Thodupuzha is believed to have constructed before 13th Century. The Ninnar Mosque near Karikkode is said to have constructed by the Vadakkumkoor Raja and this was of course for his Muslim soldiers. Thodupuzha was basically business centre. There is different historical evidence by which it can be proved that from ancient time onwards ivory, teak, rosewood, sandalwood, peacock etc., were exported to foreign countries.

Historians believe that Kuzhumoor, the capital of Chera Kings of the Sangam Age, is the Kumily in Peermade taluk. It is assumed that portions of Meenachil taluk and the whole of High Range were included in the Thanthuzhynad under the Kulasekhara Empire in A.D.800-1102. For some time these regions were under the region of the Thekkumkoor Kingdom. It was proved that Vennimala, one of the capitals of the Thekkumkoor Rajas, was in Idukki district. Manavikrama Kulasekhara Perumal established Poonjar Kingdom and Manavikraman brought Meenachil taluk and the High Range under his rule from the Thekkumkoor Raja. Thus major portions of Idukki district came under the rule of the Poonjar Raja. The whole story has many historical evidences.