The Central Statistics Office (CSO) has released details highlighting the fact that an average of 67 people live on every square kilometre.
That is compared to 62 in the previous census of 2006.
The urban population which makes up 62% of the total population in the country lives on just 2.4% of the total land area.
The fastest growing town was Saggart in South Dublin where the population grew by 150% since the last census.
Leitrim is the most rural county in the country with almost 90% of the population living in a rural setting. No county showed an increase in the share of the rural population since 2006.