Chengannur , (Malayalam: ചെങ്ങന്നൂര്) is a municipal town in Alappuzha district of the state of Kerala in South India. Chengannur (also spelled Chenganoor, Chenganur, and Chengannoor) is located in the extreme eastern part of Alappuzha district. It is 117 kilometres (73 mi) north of the state capital Thiruvananthapuram on the MC Road. Chengannur is connected to Kollam and Kottayam by NH 220. Chengannur is noted for its Shiva temple Chengannur Mahadeva Kshetram and tens of others and its Old Syrian Church. Chengannur is one of the major sabarimala pilgrim destination.

The nearest towns are Pandalam to the south, Thiruvalla to the north, Mavelikkara to the west and Aranmula, Kozhencherry, and Pathanamthitta to the east. The taluk contains villages such as Kurattissery, Mannar, Ennakkad, Pandanad, Thiruvanvandoor, Chengannur, Mulakuzha, Ala, Puliyoor, Cheriyanad, Venmony.

As of the 2001 India census, Chengannur had a population of 125,391. Males constitute 48% of the population and females 52%. Chengannur has an average literacy rate of 88%, higher than the national average of 59.5%; with male literacy of 88% and female literacy of 88%. Nine percent of the population is under 6 years of age.