Located approximately 16 kilometers northeast of Cheongju-si City, Chojeong Mineral Spring is acknowledged as one of the three major mineral springs in the world along with Shasta Spring of the U.S. and Napolinas Spring of the U.K. Chojeong Mineral Spring was discovered around 600 years ago and became nationally known ever since as the source of naturally carbonated water that has a piquant and cool taste. It is said that King Sejong (1397-1450, reign 1418-1450) visited the springs in 1444 and stayed here for 60 days to treat his eye infection. The daily yield of carbonated water here is 458 tons, which is used for producing natural soda drinks. There are presently two mineral water plant facilities in the area. The healing effects of Chojeong Mineral Spring are presumed to come from the abundant radium contained in the water, which is effective in treating eye infections and skin ailments.