Rassau, sometimes The Rassau (Welsh: Rasa (Gwenhwyseg)), is a village located in the historic county of Brecknockshire (Breconshire) and the preserved county of Gwent. It currently lies on the northern edge of the county borough of Blaenau Gwent in Wales. According to the 2011 census, the population of Rassau is 3,234. Residents often refer to either Old Rassau and New Rassau or Bottom Rassau and Top Rassau to distinguish the different parts of the village.