Almost one in five mortgages in Co Longford are in arrears - making it the county most severely affected by the property crash, according to new figures from the Central Bank.
The Central Bank has for the first time broken down the level of default on homeloans on a county-by-county basis, which shows Longford has the highest rate at 19%.
The average level of arrears nationally, measured by mortgage accounts in arrears of 90 days or more, is 11.2%.
The data shows the worst hit counties are in the border and midlands counties.
The arrears rate was 17% in Cavan, while Meath, Louth, Laois and Leitrim had arrears levels of 16%.
The lowest level of default was in Cork at 10% while the rate in Dublin was at the national average of 11%.