Almost 16% of commercial properties in Mayo are vacant at present, according to the latest figures from GeoDirectory.
The national commercial vacancy rate is at 13.2% - down slightly on the previous year.
There are almost 28,000 commercial properties in the country vacant.
Counties on the West coast had the highest commercial vacancy rates, with Sligo, Leitrim, Galway, Mayo and Roscommon making up the top five.
Sligo had the highest commercial vacancy rate at almost 19%, while at the other end of the scale, Meath had the lowest vacancy rate at 10.4% showing the widening gap between the East and West coast in terms of commercial activity.