UHG is under significant pressure heading into the weekend and has issued a public advisory.
It says the emergency department is extremely busy, and anyone not requiring urgent care could face very long waiting times.
Yesterday, more than 300 people presented to the ED, and there are 69 people on trolleys today according to the INMO.
The public are asked only to attend in the case of genuine emergency, and otherwise consider a GP or the Roscommon Injury Unit.
UHG has been grappling with high trolley numbers since before Christmas, with almost 100 patients without a bed on one occassion.