Kráľovský Chlmec (Slovak pronunciation: [ˈkɾaːʎɔʊ̯skiː ˈxl̩mɛts]; until 1948 Kráľovský Chlumec, Hungarian: Királyhelmec) is a town in the Trebišov District in the Košice Region of south-eastern Slovakia. It has a population of around 8,000.
The town was first mentioned in 1214 as Helmech. After the break-up of Austria-Hungary and 1918 partitioning of Kingdom of Hungary in the Treaty of Trianon, the town was awarded to Czechoslovakia. It was annexed again by Hungary from 1938 to 1945 as a result of controversial First Vienna Award.
Kráľovský Chlmec lies at an altitude of 130 metres (427 ft) above sea level and covers an area of 23.08 square kilometres (8.9 sq mi). It is located in the southern part of the Eastern Slovak Lowland, only around 5 kilometres (3 mi) north of Hungarian and 12 kilometres (7 mi) west of Ukrainian border. The regional capital Košice is 90 kilometres (56 mi) away.