Almost 2,700 local people over the age of 75 waited over 24 hours in an emergency department last year.
619 were in Sligo University Hospital.
The HSE target is for patients to be admitted or discharged from an emergency department within six hours.
But new figures, released under the Freedom of Information Act, reveal this target was only met in 58 per cent of cases around the country last year.
In many cases, patients had to wait over 24 hours.
Indeed, just under 7,500 people waited over 24 hours in an emergency department last year that serves the Shannonside region - that's hospitals in Mullingar, Tullamore, Galway, Castlebar, Ballinasloe and Sligo.
Almost 2,700 of them were over the age of 75 - including almost 1,800 in Galway University Hospitals, 619 in Sligo and 186 in Mullingar.
The HSE said: "It is worth noting Patient Experience Time (PET) is the length of time a patient spends in an emergency department from the time they register in an ED until they are discharged to a hospital bed or discharged home.
"Therefore it does not describe the time a patient is waiting to be seen, but the total time they spend in ED from registration."
