The Jantar Mantar, Jaipur is a collection of 19 astronomical instruments built by the Rajput king Sawai Jai Singh, the founder of Jaipur, Rajasthan. The monument was completed in 1734. It features the world's largest stone sundial, and is a UNESCO World Heritage Site. It is near City Palace and Hawa Mahal. The instruments allow the observation of astronomical positions with the naked eye. The observatory is an example of the Ptolemaic positional astronomy which was shared by many civilizations.

Jaipur is the capital and the largest city of the north-western Indian state of Rajasthan. As of 2011, the city has a population of 3.1 million, making it the tenth most populous city in the country. Located 268 km from the national capital New Delhi, Jaipur is also known as the Pink City due to the dominant color scheme of its buildings in old city.