People from about 17 properties in Clifden had to be evacuated and two schools closed in the town on the advice of Gardaí due to the torrential conditions on Wednesday.
Up to 50mm of rainfall was recorded overnight and into Wednesday, with rivers surging and flooding roads in the Connemara area.
The local authority said that Met Éireann’s warning for heavy rainfall in Connacht “did not extend to Galway”, but the weather system pushed south into the county.
After the Owenglin river burst its banks, units of Galway Fire and Rescue Service from Clifden, Carraroe and Galway city evacuated people from homes and businesses.
The Clifden Glen holiday village, and housing close to the Station House Hotel were among the properties affected.
A number of road diversions are in place and Galway County Council has appealed to drivers to exercise caution, even as the river levels recede.
A status yellow rainfall warning remains in place on Wednesday evening.
Another 15mm of rain had been forecast to fall up to 9pm tonight, with Galway County Council said its staff “remain on alert”.
The R341 Clifden to Ballyconnely road has been closed, and the N59 road close to Kylemore Abbey was still impassable on Wednesday evening.
Other stretches of the N59 which had closed earlier have re-opened, the local authority said.
Abbeyglen Castle Hotel manager Brian Hughes told RTÉ Radio 1 said that there was a “deluge of rain coming down the Owenglen river”.
Mr Hughes said he had lived in Clifden all his life, and had never seen the river burst its banks in this way.
However, older residents recalled the Owenglin bursting its banks in the 1940s during the month of August.
Gardaí have warned motorists to slow down and to avoid the affected areas if possible.
