This is the penitentiary (known as ‘Chungil Penitentiary’ — 청일교도소) that Cha Yo-han (Ji Sung) is held at during his sentence, and where part-time prison doctor Kang Si-young (Lee Se-young) comes to work at in episode 1 of Doctor John/Doctor Yo-han (의사 요한) (SBS, 2019).
Yeoju Prison [여주교도소], a presently-functioning prison which opened its doors in September 2001, is located in in the village of Sinhae-ri [신해리] in the Ganam Township [Ganam-eup/가남읍] of the city of Yeoju [여주시], Gyeonggi-do.
107 Yanghwa-ro, Sinhae-ri, Ganam-eup, Yeoju-si, Gyeonggi-do, South Korea
경기도 여주시 가남읍 양화로 107
(경기도 여주시 가남읍 신해리 212)
Geolocation (entrance — approx.): 37.235605, 127.549631
— submitted by Mich KDL