Drumnacross is a townland located in the Electoral Division of Ardara, within the Civil Parish of Killybegs Lower, the Barony of Boylagh, and County Donegal. Its Irish name is Droim na Croise.

It spans an area of 1,279,782 square metres, which equates to approximately 0.49 square miles or 316 acres.

Drumnacross shares its borders with the following townlands:

• Coraness Glebe and Kilrean Lower to the west.

• Kilrean Upper, Strawoaghter Glebe, and Tullyhonwar to the east.