Kolachel (Colachael) is a port on the Malabar coast, 20 km north of Kanya kumari(Cape Comorin), the southernmost tip of peninsular India. A Travancore fort is still present in the village. This place was the scene of the battle between the Travancore forces led by Marthanda Varma and the Dutch East Indian Company forces led by Admiral D'lennoy on August 10, 1741. The Dutch marines landed in Colachael with artillery and captured the land up to Padmanabhapuram, the then capital of Travancore. The arrival of Marthanda Varma's army from the north forced the Dutch to take up defensive positions in Colachael, where they were attacked and defeated by the Travancore forces. 28 high level Dutch officers, including Admiral D'lennoy, were captured. The defeat of the Dutch in Colachael was the turning point of the Travancore-Dutch war which had started in 1739, when Marthanda Varma annexed the domains of the native allies of the Dutch. D'lennoy went on to serve Marthanda Varma for the next 30 years and was promoted to the post of the Valiya kapptithan (commander-in-chief) of the Travancore forces. He modernised the Travancore army, and built the nedumkotta, a line of fortifications in the North of the kingdom, which held up the army of Tipu Sultan in 1791, during his ill-fated invasion of Travancore. D'lennoy is buried in the Udayagiri fort, also known as Dillanai kotta (D'lennoy's fort) which is located 7 km north of Padmanabhapuram.

The Indian government has built a pillar of victory in Colachael to commemorate the event. Colachael is currently in the Kanya Kumari District of the Tamil Nadu State of India, and is an important port on the West Coast of that state.