A total of nine cases of Covid-19 have been confirmed in Mayo.
The latest figures were released by the Department of Health today.
Elsewhere in the West, there are 35 confirmed cases in Galway, eight in Co Sligo and less than five in Roscommon and Leitrim. The data was measured at midnight last Sunday.
Yesterday, health chiefs confirmed a further 204 new cases of Covid-19 in the Republic of Ireland, bringing the total number of cases here to 1,329.
One more death has also been confirmed, bringing the total number of deaths in the country to seven.
As of midnight on Monday, 17,992 tests have been carried out in laboratories across the country, with 93% of tests returning as negative.
New rules have been introduced for Covid-19 testing, which means patients will need to meet revised criteria to qualify in future.
Patients will have to display two major symptoms – a fever and either a cough or shortness of breath – and fall into a priority group in order to be tested.
These are close contacts of a confirmed case, healthcare staff and vulnerable groups.
All patients who have not yet been swabbed, and who do not have an appointment for a test date, will not now be tested and will be required to reengage with their GP.
A testing centre was set up in Castlebar last Thursday at the Lannagh Road leisure centre. A second facility is expected to be open soon in the county town.