楽浪郡
The Four Commanderies of Han () were Chinese commanderies located in the north of the Korean Peninsula and part of the Liaodong Peninsula from around the end of the second century BC through the early 4th AD, for the longest lasting. The commanderies were set up to control the populace in the former Gojoseon area as far south as the Han River, with a core area at Lelang near present-day Pyongyang by Emperor Wu of the Han dynasty in early 2nd century BC after his conquest of Wiman Joseon. As such, these commanderies are seen as Chinese colonies by some scholars. Though disputed by North Korean scholars, Western sources generally describe the Lelang Commandery as existing within the Korean peninsula, and extend the rule of the four commanderies as far south as the Han River. However, South Korean scholars assumed its administrative areas to Pyongan and Hwanghae provinces.