The Niyamasabha Mandiram, located in Palayam, Thiruvananthapuram, is the seat of the Kerala State Legislative Assembly or the Niyamasabha. Built primarily in the classical style of Architecture of Kerala, with strong influences of many contemporary styles, it is a structure with grand staircase, gardens, water bodies and a large Central Assembly Hall. Located in a high security zone, the complex accommodates the residence of the Speaker of the Niyamasabha, legislature offices of all MLAs and offices of independent commissions and bodies. The assembly was opened on 22 May 1998, by the President of India, K. R. Narayanan.
Niyamasabha or Legislature of the State of Kerala was initially located in the Government Secretariat Complex from 12 December 1933 as the chambers of the Sree Moolam Popular Assembly and the Sri Chitra State Council, during the days of the Kingdom of Travancore. Post independence, the Assembly Hall became seat of the legislature of the newly formed Travancore-Cochin state, and later, that of the state of Kerala in 1956, after its formation. Due to the increased number of seats in the legislature of Kerala, the space became a major constraint – especially in the 1970s. In addition, space crunch was reported in the public galleries once the Assembly was opened to the general public to view the assembly proceedings. It was then decided to construct a new complex dedicated for the Assembly. In 1979, Neelam Sanjeeva Reddy, the then President of India, laid the foundation of the new complex.
The site chosen was Government Estate at Palayam, in heart of Thiruvananthapuram city, which was once the headquarters of the Nair Brigade of the Travancorean army. The old Army Headquarters was converted into the Legislature Museum.
The Niyamasabha Mandiram has 5 stories including ground floor and a basement meant for the parking of official cars. Leading to the foyer on the first floor, is a flight of 51 stairs, more than 200 feet (61 m) wide.
The entire structure is a large square with four frontages with each being supported by 40 pillars. The main entrance faces west. The West frontage has a large circular copper plate, with the Seal of Kerala inscribed on it. The foyer opens to the Central Assembly Hall, which is adorned with ornate panelling in teak and rosewood. The Central Hall is 95 feet high and has 8 galleries, which can accommodate a total of 800 people, and a Media Box. The Central Hall has 140 seats set in an amphitheatre style with a grand podium for the Speaker and 3 sets of jury tables for the Executive Staff. The background wall houses a large portrait of Mahatma Gandhi. There are microphones and electronic voting systems provided to each of the 140 seats. The central hall is lit up using 1 kW Metal Halide floodlights.
There is a large veranda, which encircles the entire structure equally. On its east side, the complex is connected to the Administrative Complex through a corridor, which houses the offices of all legislature and other independent commissions. The dome is built in traditional Kerala Koothambalam style.
The Office of the Lokayukta of Kerala is located in the Administrative office complex.
The Niyamasabha maintains 2 museums for promoting legislative awareness among public. The old Travancore Army headquarters, located inside the Niyamasabha campus, has been converted into a full-fledged Legislature museum displaying various photos and other objects & artefacts that shows the growth of the legislature in Kerala. This building is located within the Niyamasabha complex, but is separate from the Niyamasabha Mandiram. The old assembly hall inside the Secretariat was converted to legislature museum where mock assemblies are conducted to train students about legislature process along with a photo gallery.