The lake is 401 square kilometres (155 sq mi) in size and sits at a surface elevation of 186 m (610 ft).

[2] Oxford Lake is a vaguely man-shaped lake, with a 'head' on the east, a 'neck', a northwest—southeast shoulder line and a 'torso' that tapers to a point in the west.

On the northwest is a large island (Carghill Island) or peninsula that fills much of the torso.

The Hayes Rivers enters from the southwest and exits from the 'head' southeast below the town and airport of Oxford House, Manitoba.

The Carrot River enters on the northwest and allows a portage to Cross Lake, Manitoba on the Nelson River.