UHG has the country's highest number of what are termed 'stuck' patients, according to figures released to Aontú leader, Peader Tóibín.
Eight patients have been at the hospital for between 2 and 17 months, despite being cleared for discharge.
The eight patients recorded at UHG is the highest figure in the country.
Four are waiting up to five months, two are waiting between 5 and 8 months, one is waiting longer than a year, and another is waiting up to 17 months.
Meanwhile, Portiuncula Hospital in Ballinasloe does not have any patients cleared for discharge.
The reasons for why people end up "stuck" in hospitals varies, but typically it's because no suitable step-down location can be found in the community.
Among many other things, that could relate to nursing home beds, or specialist equipment and staff.
Whatever the reason, Aontú leader Peadar Tóibín says healthy people do not belong in hospital and the HSE has to tackle the situation with urgency.
