According to the 1841 census,the population was close to 6.5 million.It had been reduced by at least 2 million by 1851. Demographics of Ireland Population of the Republic of Ireland 1841-2011 6 3 2 0 g日母gggg°分9ggg According to the 1841 census, the population was close to 6.5 million. It had been reduced by at least 2 million by 1851. • Demographics of Ireland