Samhan, also known as the Three Han, refers to the Byeonhan, Jinhan, and Mahan confederacies that arose in the 1st century BCE during the Proto–Three Kingdoms of Korea. These confederacies, located in the central and southern parts of the Korean Peninsula, later evolved into the kingdoms of Baekje, Gaya, and Silla. The term "Samhan" is derived from the Sino-Korean word "Sam" meaning "three" and the Korean word "Han" which denotes "great" or "large." The name "Samhan" was also used to describe the Three Kingdoms of Korea, and the term "Han" is still prevalent in various Korean terms today. However, it is distinct from the Han in Han Chinese and the Chinese kingdoms and dynasties also referred to as Han.

The Samhan confederacies are believed to have emerged after the fall of Gojoseon in 108 BCE. They are generally perceived as loose groupings of walled-town states. Mahan, the largest and earliest of the three, was situated in the southwest and later became the foundation for the Baekje Kingdom. Jinhan, comprising 12 statelets, gave rise to the Silla Kingdom and is thought to have been located east of the Nakdong River valley. Byeonhan, also consisting of 12 statelets, led to the formation of the Gaya confederacy, which was later incorporated into Silla. The exact territories of the Samhan confederacies are a matter of debate, and their boundaries likely shifted over time. Settlements were typically built in secure mountain valleys, and transportation and trade were facilitated mainly through river and sea routes.

The Samhan era saw the systematic introduction of iron to the southern Korean peninsula, leading to advancements in agriculture and the manufacture and export of iron products, particularly by the Byeonhan states. This period also witnessed the growth of international trade, especially with the Chinese commanderies established in the erstwhile Gojoseon territories. Trade with emerging Japanese states involved the exchange of Japanese ornamental bronzeware for Korean iron. By the 3rd century, trade dynamics shifted as the Yamatai federation in Kyūshū gained control over Japanese trade with Byeonhan.