Richmond Castle is a mansion located about 2KM from Kalutara town on the Palathota road next to the Kalu river. The building is currently owned by the Public Trustee Department and is open to the public. The building was constructed by Padhikara Mudali Nanayakkara Rajawasala Appuhamilege Don Arthur de Silva Wijesinghe Siriwardena (November 12, 1889 – July 8, 1947), a local landowner and philanthropist.

The palace was built on a plan similar to a palace in India and belonged to Raja Rajeshwara Sethupathi of Ramnad, a schoolmate of Srivardhana. Sriwardena requested a copy of the building plan from Sethupathi but was advised that Sri Lanka was not capable of undertaking such a large construction project. He was greatly assisted by two local architects who secretly designed the palace.

Richmond Castle is a 16-room, 99-door, 34- windows two-story building. All the essentials for the building were sourced from abroad, with teak from Burma (used to build the main staircase), windows and vintage glass from Scotland, and iron staircases from England. In 1910 Clarice Matilda moved to Richmond Castle after marrying Maud Sooriyabandara. The marriage took place at St. Mary’s Church, Kalamulla. The couple spent 32 years together but were unable to have children. With the request to transform the palace into an orphanage, he handed over his property to the Public Trustee Department. He died on July 8, 1947. Richmond Palace has been under the care of the Public Trustee of Sri Lanka since 1956.