Serei Saophoan is the capital and largest city of the Banteay Meanchey Province and the fourth most populous city in Cambodia. The city separates Cambodia's National Highway 5 and National Highway 6. Its administrative name is "Serei Sophon" as used by the government. The more commonly used name Sisophon is derived from the Thai pronunciation Si Sophon when it was under Thai rule. Another nickname "Svay" is used mainly by truck drivers, train drivers and workers transporting goods. The origin of the word "Svay" is unknown.