Darkhan's main value is as a base for reaching two monasteries that would be difficult to visit directly from Ulaanbaatar.
Amarbayasgalant Monastery (Амарбаясгалант хийд) is the most complete surviving Buddhist monastery complex in Mongolia and the main reason to come to Darkhan. Located about 100 km east of the city, the monastery was built between 1727 and 1736 and dedicated to the lama Zanabazar — the greatest Mongolian sculptor and Buddhist scholar. It survived the Soviet purges in a damaged state and has been slowly restored since the 1990s. Getting there requires arranging a jeep and driver in Darkhan; the road involves river crossings and rough tracks through forest and steppe, and the journey takes two to three hours each way depending on conditions. The monastery is active and monks live here year-round.
Haragiin Khid is a smaller monastery close to Darkhan, accessible as a half-day excursion. It lacks the grandeur of Amarbayasgalant but is easier to reach and gives a sense of the quiet monastic life of the Mongolian steppe without the long journey.