Doochill South is a townland located in the Electoral Division of Ardara, within the Civil Parish of Killybegs Lower and the Barony of Banagh in County Donegal.

It spans an area of 746,017 square metres, which equates to approximately 0.29 square miles or 184 acres.

Doochill South shares its borders with the following townlands:

• Doochill North and Stormhill to the west.

• Gortnacart Glebe to the north.

• Monorgan Glebe and Snugborough to the east.