Braj, also known as Vraj, Vraja, Brij or Brijbhumi, is a region in India on both sides of the Yamuna river with its centre at Mathura-Vrindavan in Uttar Pradesh state encompassing the area which also includes Palwal, Ballabhgarh and Nuh in Haryana state, Deeg, Bharatpur, Karauli, and Dholpur in Rajasthan state and Morena District in Madhya Pradesh. Within Uttar Pradesh, it is very well demarcated culturally, the area stretches from the Mathura, Aligarh, Agra, Hathras and districts up to the Farrukhabad, Mainpuri and Etah districts. Braj region is associated with Radha and Krishna who according to scriptures were born in Barsana and Mathura respectively. It is the main centre of Krishna circuit of Hindu pilgrimage.

The Yamuna is the second-largest tributary river of the Ganges by discharge and the longest tributary in India. Originating from the Yamunotri Glacier at a height of about 4,500 m (14,800 ft) on the southwestern slopes of Bandarpunch peaks of the Lower Himalaya in Uttarakhand, it travels 1,376 kilometres (855 mi) and has a drainage system of 366,223 square kilometres (141,399 sq mi), 40.2% of the entire Ganges Basin. It merges with the Ganges at Triveni Sangam, Prayagraj, which is a site of the Kumbh Mela, a Hindu festival held every 12 years.