Prior to the 14th century, the area of Nakhon Ratchasima was under Khmer empire suzerainty and known in Khmer as Nokor Reach Seyma / Nokor Reach Borei, and Koreach, while Phimai to the north was probably more important.
King Narai of Ayutthaya in the 17th century, ordered a new city built on the site to serve as a stronghold on Ayutthaya's northeastern frontier. Nakhon Ratchasima was thereafter mentioned in Siamese chronicles and legal documents as a "second-class" city of the Ayutthaya Kingdom. A royal governor ruled the city in a hereditary position.
After the final phase of the Ayutthaya kingdom ended with its complete destruction by the Burmese in 1767, a son of King Boromakot attempted to set himself up ruler in Phimai, holding sway over Khorat and other eastern provinces. King Taksin of the Thonburi Kingdom (1768–1782) sent two of his generals, brothers Thong Duang and Boonma, to defeat the prince, who was executed in 1768. Thong Duang later became King Rama I of the kingdom, and Khorat became his strategic stronghold on the northeastern frontier to supervise the Lao and Khmer tributary states.
Nakhon Ratchasima Station Railway.
In 1826, Vientiane King Chao Anouvong, perceiving Siam as weakened, attacked Khorat in the Laotian Rebellion against King Rama III that was to rage on for two years.[3] Lady Mo, the wife of the deputy governor at the time, is credited with having freed the city from Anouvong's army, and has been honored with a statue in the center of downtown Khorat. A full account of the war and its impact on Laos and Siam, is well-detailed in the book, Lady Mo and Heroism at Tung Samrit, written by Frank G Anderson. The city's old wall, east of the monument was designed and built by a French engineer who is believed to be the one who also built Naraimaharaj Palace in Lopburi. The French-based design is reflected in the moat system that surrounds the innermost portion of the city.
Nakhon Ratchasima continued to be an important political and economic center in the northeastern region under the Monthon administrative reforms of the late 19th century. In November 1900, the Royal State Railways of Siam began operation of the Nakhon Ratchasima Line from Bangkok with Khorat Station as its terminus. The Ubon Ratchathani Line to the town of Warin opened 1 November 1922. The Thanon Chira Junction to Khon Kaen opened on 1 April 1933. Khorat station was changed to Nakhon Ratchasima Railway Station in 1934.
In October 1933, after the Siamese revolution of 1932 ended the absolute monarchy, the city became the headquarters of the Boworadet Rebellion, an abortive uprising against the new government in Bangkok.
In April 1981 during another attempted coup, the government, together with the royal family, took refuge in Khorat.
From 1962-1976, during the Vietnam War, Korat Royal Thai Air Force Base hosted components of the Royal Thai Air Force, the United States Air Force, and a complement of the Royal New Zealand Air Force (RNZAF). After the US withdrawal in 1976, the Thai Air Force assumed full control. During the 1980s and early 1990s, the airfield was jointly operated as a civil airport for Nakhon Ratchasima. This ended with the opening of Nakhon Ratchasima Airport in the early 1990s.
On 13 August 1993, Thailand's worst hotel disaster happened in the city, the collapse of the Royal Plaza Hotel, killing 137 people