Download coordinates as: Square Butte is the designation of a high-voltage direct current transmission line in the United States between the Milton R. Young Power Plant near Center, North Dakota at 47°4′18″N 101°11′45″W / 47.07167°N 101.19583°W / 47.07167; -101.19583 (Center Static Inverter Plant) and the Arrowhead converter station near Adolph (a neighborhood of the city of Hermantown near the city of Duluth, Minnesota) at 46°46′25″N 92°17′39″W / 46.77361°N 92.29417°W / 46.77361; -92.29417 (Adolph Static Inverter Plant).

Square Butte can transfer up to 500 megawatts at a symmetrical voltage of 250 kV.

This is the only crossing point of two HVDC overhead powerlines in the Western hemisphere.

The ground return electrode line starting at Adolph Static Inverter Plant is installed on portal pylons of the three phase AC-powerline from Adolph Static Inverter Plant to Marble Substation.

The electrode line starting at Adolph Static Inverter Plant consists of two underground 15 kV cables, each using aluminum conductors with a cross section of 380 mm2.