That's according to the latest Census figures.
The latest Census figures show that there were over 5.1 million people in the State on Census night, which took place in April last year.
That is an 8% (387,274 people) increase on April 2016 figures.
County Kildare's population increased by 11%, while the county continued to be one of the counties with the youngest age on average, at 36.9.
Nationally, the population includes more females than males.
There are 2.6 million females living in the country compared to 2.5 million males.

Kfm Obituary Notices
Firefighter Injured After Fire Engine Attacked in Kildare Town
Investigation Launched Following Death Of Man In Custody At Kildare Garda Station
Newbridge Apprentice Kyran Brady Wins National Engineering Award
Kildare EuroMillions Player Wins Over €1 Million In Special Halloween Draw
Gardaí Release Suspect Description Following Aggravated Burglary In Halverstown
Funeral Of Irish Music Legend Dónal Lunny To Take Place In Newbridge Today