Nakhon Ratchasima (Thai: นครราชสีมา, .mw-parser-output .IPA-label-small{font-size:85%}.mw-parser-output .references .IPA-label-small,.mw-parser-output .infobox .IPA-label-small,.mw-parser-output .navbox .IPA-label-small{font-size:100%}pronounced [ná(ʔ).kʰɔ̄ːn râːt.t͡ɕʰā.sǐː.māː]) is the capital of Nakhon Ratchasima province, the largest city in Northeastern Thailand and the third-largest city in Thailand. It is 250 km (155.43 mi) northeast of Bangkok, one of the four major cities of Isan (Northeast Thailand), known as the "big four of Isan", and has a population of 466,098 people as of 2021. The city is commonly known as Korat (โคราช, pronounced [kʰōː.râːt]), a shortened form of its name. Korat is at the western edge of the Korat Plateau. Historically, it once marked the boundary between Lao and Siam territory. It is the gateway to the Lao-speaking northeast of Thailand. Archaeological evidence suggests that in Sung Noen District 32 km west of present-day Nakhon Ratchasima (Korat) there were two ancient towns called Sema ("Bai sema" (ใบเสมา) are notable artifacts of the Korat plateau)[citation needed] and Khorakapura. (Pali púra becomes Sanskrit puri, hence Thai (buri), all connoting the same as Thai mueang: "city with defensive wall".) N The latter name was shortened to Nakhon Raj. (Nakhon (นคร) derives from Sanskrit nagara (नगर), "city"; Raj (ราช), from Sanskrit Raj, "sovereign.") The present city name is a portmanteau of Nakhon Raj and Sema.