Completed in 1869, this British-Malay-Indian hybrid building was once the Government House of the colony of Singapore, before being repurposed upon independence as the official residence of the President. The 100-acre grounds occupy some of Singapore's choicest real estate and incorporate several gardens and even a 9-hole golf course. A separate building on the Istana grounds known as Sri Temasek serves as the official residence of the Prime Minister, though no prime minister has ever lived there. There is a Changing of the Guards ceremony every first Sunday of the month at 5.45pm, with rifle-twirling displays by the military police. The Istana is open to the public on only five days a year: Chinese New Year, Deepavali, Hari Raya Puasa, Labour Day and National Day. Apply online in advance for tickets.

The Istana houses the offices of the President and Prime Minister of Singapore and is a venue for state events and important official functions.

The Istana is also the office of the prime minister of Singapore and contains Sri Temasek, the official residence of the prime minister since Singapore's independence in 1965, though none of the prime ministers have ever lived there.

The 106 acres (0.43 km2) estate was once part of the extensive nutmeg plantation of Mount Sophia. In 1867, the British colonial government acquired the land and built a mansion to be the official home of the British governor. This continued until 1959 when Singapore was granted self-governance, and the governor was replaced by the Yang di-Pertuan Negara, who was in turn replaced by the president of Singapore.

The Istana was gazetted as a national monument on 14 February 1992.