It is an example of 'Hindu-Rajput' Nepali architecture. It is often considered the most important model of Rajput architecture in Nepal. Fully built in bright white and constructed in an area of 4,860 sq. feet in a mixed style of Islamic and Rajput domes, the temple is 50 meters high. It is a three-storied structure made entirely of stone and marble. All its 60 rooms are decorated with the flag of Nepal, colored glass, engravings and paintings, with beautiful lattice windows and turrets. According to legends, King Janak ruled this area (called Mithila Desh) during the Ramayana period. His daughter Janaki (Sita), during her swyambar, had chosen Lord Rama as her husband, and become queen of Ayodhya. There marriage ceremony is believed to have occurred in the nearby Temple.
The temple is popularly known as the Nau Lakh Mandir (meaning Nine Lakhs). The cost for the construction of the temple was about the same amount of money: Rupees Nine Lakhs or Nine Hundred Thousands and hence the name. Government of Kingdom of Nepal and Queen Vrisha Bhanu – of Tikamgarhm, India provided aid to Gurkha Soldier General Amar Singh Thapa to build the temple in 1910 AD. In 1657, a golden statue of the Goddess Sita was found at the very spot, and Sita is said to have lived there. The legend had it that it was built on the holy site where Sannyasi 'Shurkishordas Nepali had found the images of Goddess Sita. In fact, Shurkishordas was the founder of modern Janakpur and the great saint and poet who preached about the Sita Upasana (also called Sita Upanishad) philosophy. Legend has claimed it that King Janak(Seeradhwaj) performed the worship of Shiva-Dhanus on this site.
Every year, thousands of pilgrims from Nepal, India, Sri Lanka and other countries visit Ram Janaki Temple to worship Lord Ram and Sita. During the festivals of Ram Nawami, Vivaha Panchami, Dashain and Tihar, there is presence of even more worshipers.