Downtown Seoul (Korean: 서울 도심; 서울 도심부; 서울 시내), also known as Seoul Central Business District or Sadaemun-An, is traditional city center and central business district of Seoul, located through Gwanghwamun of Jongno District and Seoul Station of Jung District along the Sejong-daero and Jong-ro. For its time-honored and unique geographic status in Seoul, the downtown is usually just called the Central Business District (Seoul CBD), or sometimes Gwanghwamun Business District for the landmark 'Gwanghwamun' at the heart of it.

Seoul in the age of Joseon was called Hanyang (or by official name of its administrative division and governing authority Hanseong-bu). As it was a walled city, presence of the Seoul City Wall made great influence on imagined geographies of Seoul, like the London Wall surrounding Londinium. By the Seoul City Wall, Hanseong-bu was divided into two regions; an urban downtown space named as Seong-jung (성중; 城中) or Doseong-an (도성 안; lit. 'inside the capital city wall') area inside the city wall, and peripheral areas named Seongjeosimni (성저십리; 城底十里) which was a ring-shaped region 10 ris (Korean mile) outside of the City Wall.

Seoul was a planned capital of the Joseon, as geographic embodiment of Confucianism. The cityscape of Hanseong-bu's downtown area was also created by adaptive cultural diffusion of Confucianism. According to Confucian classics, construction of capital city (도성; 都城) should follow several Confucian principles on city planning. For example, Rites of Zhou instructs principle of '左祖右社 面朝後市' (좌조우사 면조후시), which means 'With the main palace at the center, Confucian royal ancestral shrine (祖) goes to the left, Altar of Soil and grain (社) to the right, cabinet buildings (朝) to the front, and marketplace (市) to the behind'. Following this Confucian instruction, Jongmyo and Sajikdan were placed on the left and the right of the main palace Gyeongbokgung. Also, Six Ministries, cabinet of the Joseon government was placed right in front of Gyeongbokgung's main gate Gwanghwamun. Government buildings and official residences for the Six Ministries were built on both sides of the road just outside of the Gwanghwamun, and the road was called Yookcho Street [ko] (육조거리; lit. 'Street for the Six Ministries' or 주작대로; lit. 'Mainstreet of the Vermilion Bird'). However, Joseon could not place the official marketplace behind Gyeongbokgung, because the main palace Gyeongbokgung was built almost right in front of the mountain Bugaksan. So Joseon had to detour instructions from Rites of Zhou, by building the only licensed-official market in Seoul, the Sijeon [ko], along the Unjongga (now Jongno street), which was southeast side (front side) of the main palace.

This adjusted city planning in early Joseon created continuous commercial area in form of east-west axis around the Jonggak belfry, starting from southern end of the Yookcho Street [ko] to eastern end of the Unjongga (located near present-day Wongaksa Pagoda). This traditional cityscape of Hanyang city's downtown area is still continued even in present-day Seoul, even through two major wars (Japanese and Qing invasion) in Joseon dynasty, colonial governance of Japanese Empire, and the Korean War after liberation. Government Complex Seoul along the Sejong-daero (former Yookcho Street), and headquarters of largest companies around Jongno are clear examples of such time-honored history and tradition.

In reign of the Korean Empire, the name of Seoul was Hwangseong (황성; 皇城, meaning 'City of the Emperor'. Structural modernization in cityscape of Hwangseong's downtown area was started during initial decade of the Korean Empire, when the empire sustained political autonomy. For example, from 1898 to 1904, when the Korean Empire maintained autonomy in state governance, tram (1899) and electric street light (1900) were first introduced to Downtown Seoul's cityscape. Also, the Korean Empire's first Emperor Gojong relocated substantial parts of main palace's function from Gyeongbokgung to Deoksugung, and introduced modern railway transportation. These reforms led to strategic expansion of roads connecting Gyeongbokgung, Deoksugung and the Seoul Station, creating another important cityscape in downtown Seoul as form of north-south axis.

However, as the Korean Empire lost substantial autonomy after signing Treaty of 1905, Japanese colonial officials began to drive cityscape reconstruction. Spatial reorganization in this early colonial period was targeting subordination of Korean Empire's royal government and advancing authority of colonial government. Some of notable tough reforms during this period includes reconstructing royal palaces into public parks and zoo, and modernizing city roads.

Although the area of Downtown Seoul inside the city wall had maintained a single integrated urban sphere for about 600 years through Joseon dynasty and Korean Empire, Japanese Government-General on Colonial Korea divided Keijō's downtown area into two modern administrative divisions of Keijō in 1943; Jongno District and Jung District. This abrupt division explains why it is hard to explain pre-modern history of Jongno District and Jung District separately.

Abrupt partition of Downtown Seoul's urban structure by Japanese colonial government was influenced by ethnic distribution inside the area. During the early periods of Colonial Korea, most of Japanese people were living in southside of the Cheonggyecheon inside the City Wall, an area named by Koreans as Namchon (남촌; lit. 'Southern village'), compared to Bukchon (북촌; lit. 'Northern village') where most of influential Koreans were living in. Despite the actual geographic dissociation between Japanese and Korean were getting mitigated over time, this geographic stereotype later encouraged local government of Keijō-fu to divide area of Downtown Seoul into Jongno District and Jung District, according to natural boundary of the Cheonggyecheon. Most of Keijō's influential economic institutions were newly constructed in southside of the Cheonggyecheon, even famous in the current names of Myeong-dong and Sogong-dong. Key examples of these buildings include Bank of Chōsen and Keijō Post Office. In contrast, native Korean people lived in relative squalor in Bukchon, an area to the north of Cheonggyecheon. The famous hanok town in Bukchon Hanok Village, created from the 1910s to 1930s during the colonial period, is one of symbolic space showing such ethnic disparity inside modern Keijō.