The rivers flowing to the western region are Neyyar, Karamana, Vamanapuram, Ittikara, Kallada, Achankovil, Pamba, Manimala, Meenachil, Muvattupuzha, Periyar, Chalakudy, Karuvannur, Keechaery, Bharatpuzha, Thirur, Pooraparambu, Kadalundy, Chaliyar, Kallayi, Korapuzha, Kuttiyadi, Mahi, Thalassery, Ancharakandi, Valapattanam, Kuppam, Ramapurampuzha, Perumba, Kavvayi, Kariyankodu, Neelaeswaram, Chittar, Beckal, Kalnadu, Chandragiri, Mogral, Kumbala, Shiriya, Uppala and Mancheswaram. These rivers merges to the Arabian sea or the back-waters which merges to the Arabian sea.

Rivers flowing west and their length in Kms.

Name	Length In Kms	Name	Length In Kms
Periyar	244	Mahi	54
Bharatapuzha	209	Keecheri	51
Pamba	196	Prumba	51
Chaliyar	169	Uppala	50
Chalakudy	169	Karuvanoor	48
kadalundy	130	Anjarakkandi	48
Achankoil	128	Tirur	48
Kallada	121	Neeleshwaram	46
Muvattupuzha	121	Pallikkal	42
Valapattanam	110	Korappuzha	40
Chandragiri	105	Mogral	34
Manimala	90	Kaveripuzha	31
Vamanapuram	88	Puzhakkal	29
kuppam	82	Thalassery	28
Meenachil	78	Manam	27
Kutyadi	74	Chittary	25
karamana	68	Kallai	22
Shiriya	68	Ramapuram	19
Karingode	64	Ayiroor	17
Ithikkara	56	Bangra Manjeswara	16
Neyyar	56

Rivers flowing East and their length in Kms.
Kabani	63 kms	Bhavani	39kms	Pambar	26kms