Radha Kund / Syama Kund are located about 26 km west of Mathura.
Syama kund appeared after Lord Krishna killed the demon Aristasura. Because Aristasura was in the form of a bull, the gopis told him that he had made an offence and had to purify Himself by bathing in all the holy tirthas. Rather than travel to all the holy places, the Lord brought all the holy places to that spot. He struck the ground with His heel and immediately all the waters from all holy rivers appeared. This place became known as Syama kund.
In a competitive mood, the gopis led by Radha also created a kund by digging the earth with their bangles. All the holy rivers then petitioned Radha to allow them to enter Her new Kund. Thus Radha kund appeared. In the center of Radha Kund is a small walled-in area called Kancana Kund. This kund is said to mark the location of the original kund that Radha and the gopis dug with their bangles.
Radha kund and Syama kund were unknown for a long time until they were discovered by Sri Chaitanya Mahaprabhu in 1515. Any person who bathes in the sacred waters of Radha / Syama kund is believed to blessed by Lord Krishna.