Over 152,000 people are living in Longford, Leitrim and Roscommon according to new figures from the Central Statistics Office.
The results of the 2022 Census were released today with each of the three counties in the Shannonside Region seeing population growth of an average of 11 percent since 2016.
It's the first time in 171 years that Ireland's population exceeded the five million mark, with 5.14 million people living in the country.
Local population levels saw significant growth over the last 6 years, with 152,209 people identified as living in the region.
Roscommon recorded the highest figure with the CSO data showing 70,260 people living in the county, an increase of 9 percent on the previous 2016 census.
That's followed by Longford, where population levels grew by 14 percent in the past 6 years to 46,751, while there were 35,200 people living in Leitrim as of 2022.
When looking at the gender difference, the figures show there were slightly more males than females across the three counties last year, with 76,172 men and boys versus 76,037 women and girls.
While the average age in the country was recorded to be almost 39 years of age, Roscommon and Leitrim saw higher average ages of over 40 years, up from 39 in 2016.
When it comes to children, there were close to 31,000 children aged 15 and under in the Shannonside region, with over 14,000 in Roscommon, 9,728 in Longford and 7,161 in Leitrim.