Gurudwara Chilla Sahib in Sirsa is a historically important gurdwara marking the site where Guru Nanak Dev Ji performed a 40-day meditation (chilla) during his second Udasi. The Guru spent over four months in Sirsa, and during this time he engaged with Muslim fakirs Pir Bahawal and Khwaja Abdul Shakur at a local fair, passing their spiritual tests and demonstrating the supremacy of divine truth. Originally maintained by Muslim priests of a khanaqah until Partition in 1947, the site has since been developed into a gurdwara complex that also runs a school and charitable hospital.