The number of families in County Donegal has fallen while it has increased in Sligo and Leitrim.
And the number of people divorced has risen in all three counties, the biggest increase being in Donegal.
The figures, just released, are from an analysis of households and families, details of which were collected as part of Census 2016.
The Census recorded that there were 41,134 families in County Donegal, a fall of 220, or 0.5%, on the figure in the previous census in 2011.
In County Sligo, there were 16,664 families, an increase of 348, or more than 2%, on 2011.
And in Leitrim, there were 8,298 families, an increase of 118, or almost 1.5%.
In Donegal, the number of divorcees increased by 413 to 3,362, in Sligo by 163 to 1,375, and in Leitrim by 122 to 727.
There were 1,866 remarried persons in Donegal, 746 in Sligo and 541 in Leitrim.
Census 2016 was the first time that same-sex civil partnerships were recorded.
When the Census was taken last year, there were 59 people in this category in Donegal, 42 in Sligo and 17 in Leitrim.
