~51km/2hrs from Shimla on the Sutlej, only ~650m above sea level so noticeably warmer. The original hot springs were submerged by the Kol Dam reservoir; today's hot water comes from bore wells feeding pools at hotels and public facilities - a pleasant soak, not a resort-style spa. The Sutlej also runs commercial rafting when conditions allow; confirm what is operating before committing the day.
Tattapani, whose name combines the local words 'tatta' (hot) and 'pani' (water), sits on the banks of the Sutlej River roughly 50 km from Shimla and has long been a pilgrimage site, especially during Makar Sankranti when devotees bathe in the sulphur-rich waters believed to cure joint and bone ailments. Local legend attributes the springs to the sage Jamadagni's penance in the Treta Yuga, or alternatively to Lord Krishna wringing hot water from a wet towel. The original springs were submerged by the reservoir of the 800 MW Kol Dam hydroelectric project completed in 2015, prompting authorities to reroute the thermal water through bore wells to newly built bathing kunds on higher ground.