Front line staff at University Hospital Limerick had to cope with nearly three times more patients on trolleys last month compared to the next most overcrowded facility.
According to the Irish Nurses and Midwives Organisation 1,824 people were without a bed at the hospital during July which serves North Tipp, Limerick and Clare.
Sligo University Hospital was next in line with 615.
TUH in Clonmel had 85 patients on trolleys last month while Nenagh General had 6.
So far this year 11,787 patients were left without a bed at UHL from a total of almost 72,400 across all hospitals.