Sligo University Hospital was one of the most overcrowded facilities for the month of May.
Nationally, 11,856 people, including 300 children were on trolleys over the course of the month, according to the Irish Nurses and Midwives Organisation.
A total of 751 people awaited admission to Sligo University Hospital in May, making it the fourth most overcrowded hospital in Ireland.
The Irish Nurses and Midwives Organisation has called on the HSE to take immediate corrective measures to deal with the ongoing trolley crisis.
In a statement INMO General Secretary, Phil Ní Sheaghdha said that this type of overcrowding at the beginning of summer must be immediately addressed to prevent an even more chaotic winter.
