The census is of particular note in Ireland as it was taken shortly before the Great Famine (1845-1852), which resulted in over 1 million deaths and spurred decades of mass emigration.

[5] Very few census records for Ireland prior to 1901 survive due to the Irish Public Office being bombed on 30 June 1922.

Carlow was consistently recorded as Ireland's least populous county until the 1956 census, when Longford dropped below it.

Partially owing to their mountainous terrain, counties Kerry, Donegal and Wicklow were the island's least densely populated regions.

[8] The census recorded that the population of England, Scotland and Wales combined was just over twice that of Ireland, at 18.55 million.