The Department of Education conducted research into class sizes.
It has been revealed that 45 students were sharing a classroom in Westmeath last year.
The figures from the Department of Education show the largest classrooms recorded were in Dublin and Meath.
Speaking on the matter - Sinn Féin Education Spokesperson Donnchadh O'Laoghaire said, "there is social distancing in higher classes at primary school level. Space, whether primary or post-primary, is at a premium"
He went on to add that "the largest overcrowding tends to happen in primary schools" and that high numbers are "bad for education, very bad for social distancing and ensuring this return to school is sustainable."
Many schools opened their doors this week for the new academic year.
