A status yellow rainfall warning for the region overnight ended at 8am and has resulted in extensive surface water on many roads and floods in places.
Gardai are advising motorists to slow down and take due caution as a result.
The Neale to Ballinrobe road remains closed to traffic this morning due to flooding.
Alan O'Reilly from Carlow Weather says areas along the River Shannon are particularly badly affected.
It's feared the heavy rain will lead to flooding in areas along the River Shannon in the coming days.
Kevin Murray's family owns a farm shop in Ballinasloe, Co. Galway.
He says when the main course of the Shannon backs up, their business on the banks of the River Suck is at risk.