Two places come to mind, both in Manitowish Waters (less than an hour south of Ironwood)
Blue Bayou Inn (on Lake Manitowish, right on US 51 - which is what I39 turns into north of Tomahawk)
Not as good as it used to be before Chef Walter passed away, but still the best Cajun & Creole food in Northern Wisconsin)
(715) 543-2537
Pine Baron's (about a mile north of US 51 on County Road W)
Surprisingly good upscale food for the area.
(715) 543-8464
here are more options in that area:
http://www.manitowishwaters.org/eat_drink.htm