The temple's origins are steeped in legend. It is believed that a merchant while transporting the enormous idol of Hanuman Ji, drowned in the Ganges as his boat became heavy near Prayag. The idol then materialised at the same location where the temple was later built. Another legend tells of a childless king from Kannauj who was instructed by his Guru to install a Hanuman statue in his kingdom. The king transported the statue by boat, but when he reached Prayag, the boat broke, and the deity submerged. The deity was later discovered by a Ram devotee named Baba Balagiri Ji Maharaj when the water level of the Ganges dropped. The idol, believed to be 600-700 years old, is 20 feet long and 8 feet wide.

The Sankatmochan Mandir holds great significance for its devotees. It is believed that after receiving the blessing of Hanuman Ji in this temple, the benefits of taking a bath in the Maha Kumbh are completed. The entry of water into the temple is considered lucky, and Hanuman Ji's bath in the Ganges is seen as a sign of good fortune for the country. The temple is particularly crowded on Tuesdays and Saturdays, which are considered auspicious days for Hanuman worship.

The Hanuman Mandir is unique in its architectural design. The idol of Hanuman Ji is installed in the temple's sanctum sanctorum, which is situated 8.10 feet below the temple itself. The idol is in a reclining position, a feature that sets it apart from other Hanuman temples.

Besan Laddoo, Bundi, and Tulsi garlands are offered to Bajrangbali in Sankat Mochan temple. Devotees also offer fruits and dry fruits to Hanumanji.