It spreads out in Alappuzha and Pathanamthitta districts having 51 churches and 10 chapels.

Dr Thomas Mar Athanasios Kizhakkethalakkal became the first Metropolitan of the Diocese of Chengannur on 1 August 1985.

In 2018 the then Malankara Metropolitan H.H Baselios Marthoma Paulose II appointed H.G.

Baselios Marthoma Mathews III was enthroned as the Malankara Metropolitan, also taking charge of Chengannur.

Dr Mathews Mar Thimotheos became the Metropolitan of the diocese of Chengannur.