Sahibzada Ajit Singh Nagar district (SAS Nagar district)), also known as Ajitgarh district, is one of the twenty two districts of Punjab a state in north-west India. It was formed in April 2006 and is 18th district of Punjab, created next to Pathankot district. This district was carved out of areas falling in Ropar and Patiala District.

SAS Nagar is named after the eldest son of Guru Gobind Singh, Sahibzada Ajit Singh which means “House of Sahibzada Ajit Singh”.

According to the 2011 census, SAS Nagar district has a population of 986,147, roughly equal to the nation of Fiji or the US state of Montana.This gives it a ranking of 450th in India (out of a total of 640).The district has a population density of 830 inhabitants per square kilometre (2,100/sq mi).Its population growth rate over the decade 2001-2011 was 32.02%.SAS Nagar has a sex ratio of 878 females for every 1,000 males, and a literacy rate of 84.9%.