Samhan, or Three Han, is the collective name of the Byeonhan, Jinhan, and Mahan confederacies that emerged in the first century BC during the Proto–Three Kingdoms of Korea, or Samhan, period. Located in the central and southern regions of the Korean Peninsula, the Samhan confederacies eventually merged and developed into the Baekje, Gaya, and Silla kingdoms. The name "Samhan" also refers to the Three Kingdoms of Korea.

The Samhan are thought to have formed around the time of the fall of Gojoseon in northern Korea in 108 BC. Kim Bu-sik's Samguk Sagi, one of the two representative history books of Korea, mentions that people of Jin Han are migrants from Gojoseon, which suggests that early Han tribes who came to Southern Korean peninsula are originally Gojoseon people. However, the state of Jin in southern Korea, which its evidence of actual existence lacks, also disappears from written records. By the 4th century, Mahan was fully absorbed into the Baekje kingdom, Jinhan into the Silla kingdom, and Byeonhan into the Gaya confederacy, which was later annexed by Silla. Beginning in the 7th century, the name "Samhan" became synonymous with the Three Kingdoms of Korea.

The Samhan saw the systematic introduction of iron into the southern Korean peninsula. This was taken up with particular intensity by the Byeonhan states of the Nakdong River valley, which manufactured and exported iron armor and weapons throughout Northeast Asia. The introduction of iron technology also facilitated growth in agriculture, as iron tools made the clearing and cultivation of land much easier. It appears that at this time the modern-day Jeolla area emerged as a center of rice production (Kim, 1974).