The answer to the crossword for the term 'County South of Donegal' is Sligo, which is a county in the Republic of Ireland. It is located in the province of Connacht and borders the Atlantic Ocean to the west, County Leitrim to the north, County Roscommon to the east, and County Donegal to the north-east. Sligo is known for its beautiful landscapes, including Benbulben mountain, and its rich cultural heritage.