The 289 feet high Mahaweli Maha Seya, which is second in its dimension only for Ruwanweli Maha Seya in Anuradhapura has been built near the Kotmale Reservoir, under the Mahaweli Scheme.

 
The Mahaweli Maha Seya was a concept of the former Minister of Mahaweli Development, late Gamini Dissanayake in memory of the old submerged temples and the people who lost their properties when the Kotmale Reservoir was built.

Former President, late J. R. Jayewardene laid the foundation stone for the Mahaweli Maha Seya in 1983 and it was completion after 33 years and opened to public.

Speaking at the ceremony the President expressed his pleasure to open this Chaithya as the sixth President of the country, which the foundation stone was laid by the first Executive President of Sri Lanka.

President expressed his praiseworthy thanks to the Minister Naveen Dissanayake, the son of the late Minister Gamini Dissanayake and his family as well as the Buddhist monks led by the Chief Incumbent of temple of Mahaweli Maha Seya Ven. Thispane Jinananda Thero for completing this task.

 
The Maha Sangha including Most Ven. Vimaladhamma Anu Nayake Thero, Chief Prelate of the Ramanya Sect, Most Ven. Napane Pemasiri Thero, Ven. Dr. Ittapana Dhammalankara Anu Nayake Maha Thera, Ven. Prof. Bellanwila Wimalaratana Anunayake Thera, Ven. Thiniyawala Palitha Thero, Prime Minister, Ranil Wickremesinghe, and the Speaker Karu Jayasuriya, were also participated.