Ancient history to the Later Three Kingdoms Era It is unclear exactly when humans first inhabited the Daejeon area. However, the Paleolithic site of
Seokjang-ri in nearby
Gongju, Chungcheongnam-do, and the
Yongho-dong site in
Daedeok District, Daejeon, suggest that people lived here from around that time. From the
Bronze Age, artifacts such as bronze items, dwelling sites, and pottery have been excavated, providing concrete evidence of sustained human habitation. During the
Proto–Three Kingdoms Period, the area was part of
Mahan, one of the Three Han states. It is believed to have been home to
Sinheunguk (臣釁國), one of the small states that made up Mahan. However, some theories place Sinheunguk in
Seosan or
Yesan County in
South Chungcheong Province, so its exact location is uncertain. Proponents of the Daejeon theory speculate that "Sinheung" is related to Jinhyeon-hyeon, which will be discussed later and eventually connects to the place name Jinjam-dong. Meanwhile, the area around the now Yuseong District is thought to have been the site of Naebiri-guk (內卑離國) of Mahan. This is because the Three Kingdoms-era place name for Yuseong District, Nosaji, is also recorded as Naesaji (內斯只), and both names share the element "Nae" (內). In the
Three Kingdoms Period, the area became part of
Baekje's territory and was known as Usul-gun (雨述郡), centered around Eumnae-dong in Daedeok District and including Hoedeok-dong. ''Also on Usul-gun, in the city exists the remains of Bakjae's mountain fortress Usul-fortress
(), which was declared a city-designated monument in 1989
. This name is a transcription of the native Korean place name "Bisul" or "Bisuri," where they took the meaning "rain" from the character 雨 and the sound "sul" from 述. At Gyejoksan Mountain in Jang-dong, Daedeok District, there is a legend that "when the mountain cries during severe drought, rain comes," leading to the place name "beak-dal-san" or "beakdal" mountain, and "Bisuri," () meaning "rainy peak." This legend is also recorded in early Joseon-era texts like the Geographical Appendix to the Annals of King Sejong and the Sinjŭng Tongguk yŏji sŭngnam'' (), the version of
Tongguk yŏji sŭngnam, updated in 1530. Under Usul-gun, there were Nosaji-hyeon (奴斯只縣) in the area of Guseong-dong, Yuseong District; Sobipo-hyeon (所比浦縣) in Deokjin-dong; and Jinhyeon-hyeon (眞峴縣) in Bonggok-dong, Seo-gu. Among these, Jinhyeon-hyeon was the only one not under Usul-gun but belonged to Hwangdeungyasangun (黃等也山郡), centered around Yeonsan-myeon in Nonsan, South Chungcheong Province. Based on the Five Divisions established during King Seong(성왕;year 504 ~557 july)'s reign(523 may~ 554 july), the area around Gongju was the Northern Division, and the area around Nonsan was the center of the Eastern Division, so it likely belonged to one of these two. Considering that the Daejeon area later generally moved in conjunction with Gongju, the dominant theory is that it belonged to the Northern parts of regional classification. During this period, the area was one of the main frontlines among Goguryeo, Baekje, and Silla, resulting in many mountain fortress ruins in Daejeon, leading to an oral tradition that the name of Sikjang Mountain originated from the Baekje army storing provisions on the mountain. There are also numerous fortifications that are closer to small forts than large mountain fortresses. Notably, after Baekje's King Gaero had Wiryeseong captured by Goguryeo's King Jangsu, Baekje faced a critical crisis due to continued southward advances by Goguryeo. The Goguryeo army reached as far as the Daejeon area, creating an unprecedented situation where Baekje's Ungjin Fortress was pressured from both the northeast (Sejong) and southeast (Daejeon). Relics left by the Goguryeo army from this time can be found in Wolpyeong-dong in Seo District, Daejeon, as well as in Bugaang-myeon, Saerom-dong, and Naseong-dong in Sejong. It was not until the reign of King Dongseong that Baekje, allied with Silla, succeeded in driving out the Goguryeo forces from the Daejeon area. Baekje recovered the entirety of Sejong, most of Cheongju, and most of Daejeon. However, they had to tolerate Silla's occupation of the entire Goesan area—which was originally part of Hanseong Baekje's territory—as well as the northern half of now Daedeok District and the southwestern part of Cheongju. Goesan was recovered from Silla during the reign of King Uija of Baekje, but the Sintanjin area and the southwestern part of Cheongju were never regained until Baekje fell. Therefore, the northern region of Daedeok District has deep historical connections not only with Baekje but also with Silla. During the wars for the unification of the Three Kingdoms in 660, there is a record that the Silla army stationed at Nosurisan (怒受利山) during the
Battle of Hwangsanbeol, which broke out on July 9. Given the phonetic similarity to Nosaji-hyeon located in Yuseong District, it is considered to be the same place. As the Daejeon area was a border region adjacent to Hwangdeungyasangun (
Nonsan), a fierce battleground, it would have been suitable for the Silla army to set up camp. After the fall of Baekje, the area became the backdrop for the Baekje Revival Movement. The Ongsanseong (甕山城), where the revival forces blocked the Silla army's path and fought around August 661, is presumed to be Gyejoksanseong Fortress on Gyejoksan Mountain in Jang-dong, Daedeok District. After a three-day siege, Ongsanseong fell on September 27. Subsequently, Usul-gun was attacked by Kim Pumil, the governor of Sangju, and over 1,000 people were executed. According to records, Jo Bok (助服), the last military commander of Usul-gun and a second-rank Dalsol, surrendered to Silla along with a third-rank Eunsol named Paga (波伽) and their followers. Later, in August 662, remnants of the revival forces gathered and fortified themselves at Naesajiseong (內斯只城), presumed to be the fortress located in the aforementioned Nosaji-hyeon (奴斯只縣) which corresponds to the now Yuseong District area, and resisted, prompting the dispatch of 19 generals, including Kim Heumsun, to defeat them. In the
Unified Silla period, based on Silla's
nine provinces and five secondary capitals policy, the area belonged to Ungcheonju (熊川州). Later, due to King Gyeongdeok's Sinicization policy in 757, Usul-gun was renamed Bipung-gun (比豊郡), Nosaji-hyeon became Yuseong-hyeon (儒城縣), During the Later Three Kingdoms period in the early 900s, the area came under the territory of Later Baekje. Compared to the original Baekje, Later Baekje's domain extended much further east beyond Daejeon, deeply into Gyeongsang-do, and had also reclaimed the northern part of Daedeok District, which had previously been occupied by Silla. Therefore, the area of Daejeon belonged to Later Baekje until its collapse in 936.
Goryeo Dynasty Entering the
Goryeo period, Bipung-gun (比豊郡) was renamed Hoedeok-hyeon (懷德縣), Jeokjo-hyeon (赤鳥縣) became Deokjin-hyeon (德津縣), and Jinryeong-hyeon (鎭嶺縣) was changed to Jinjam-hyeon (鎭岑縣), while Yuseong-hyeon remained unchanged. According to the ten provinces established during King Seongjong's reign, the Daejeon area belonged to Hanam-do. All four prefectures were subordinate to Gongju-mok (公州牧), which had been elevated to one of the twelve administrative districts known as "mok." Later, during King Hyeonjong's reign, the implementation of the Five Provinces and Two Frontier Regions system placed the four prefectures under Yanggwang-do. Gongju-mok was downgraded back to simply Gongju, but the four prefectures remained its subordinate counties. Subsequently, during King Myeongjong's reign, Hoedeok-hyeon and Jinjam-hyeon were promoted to "ju-hyeon" (main counties), and officials known as "Gamwu" (監務) were dispatched, initiating independent administration. This autonomy continued into the Joseon Dynasty, where they remained separate districts. However, Yuseong-hyeon and Deokjin-hyeon did not gain independence and continued as subordinate counties of Gongju. Meanwhile, there were special administrative districts called "hyang," "bugok," and "so." Among these, the most famous was Myeonghakso (鳴鶴所), known as the site of the Mang Yi and Mang Soi Rebellion. This area is believed to have been located in what is now Tanbang-dong in Seo-gu.
Joseon Dynasty During the
Joseon period, Hoedeok-hyeon and Jinjam-hyeon were each elevated to Hoedeok-gun and Jinjam-gun, respectively. The area that is now the central part of Daejeon remained a small rural village within Gongju, which had been re-elevated to Gongju-mok during the reign of King Chung-hye of Goryeo. Notable figures like Song Si-yeol of the Eunjin Song clan lived in this vicinity, and the place name Songchon-dong, related to them, still exists as one of Daejeon's districts. Additionally, the Hoedeok Hwang clan established their base in the Hoedeok-hyeon area. Meanwhile, the name "Daejeon" (大田), which is the
Hanja transcription of the native term "Hanbat" () for
Great Fields, first appeared in records in the early Joseon period, in
Tongguk yŏji sŭngnam, and continues to be used today. However, the now Yuseong area remained part of Gongju until it was transferred during the establishment of Daejeon-gun in 1914. With Yuseong joining Daejeon-gun, the region roughly restored the combined territory of the central area and its subordinate prefectures from the times of Usul-gun and Bipung-gun. With the construction of
Sejong Special Self-Governing City in 2013 for the division of capital functions and balanced local development, many of the public institutions that had previously headed to Daejeon were moved to Sejong, and many public institutions in
Seoul were also moved to Sejong. With the launch of Sejong City, large-scale development began, resulting in infrastructure construction and large-scale apartment complexes. Sejong is located immediately north of Daejeon, and Daejeon citizens began to outflow to Sejong. As of July 2020, there was net outflow of more than 100,000 people from Daejeon to Sejong. ==Geography==