Dennis (Denny) Hannifin (known by the nicknames “Eccentric Denny” and the “Squatter Governor”) was an early Bismarck pioneer, gambler, and businessman. He was a professional gambler, established one of the first local saloons, and held various investments in coal and land.
Hannifin was born in Ireland in 1835 and immigrated at age 10. He was educated in Buffalo, NY and served as a second lieutenant with the Union Army until 1863.
He arrived in Dakota Territory in 1868 – four years before the town that became Bismarck was founded. Upon discovering a coal seam west of present-day Mandan, he established Fort Hannifin to secure his interest and hold off Native Americans.
Hannifin reportedly is credited with convincing Colonel Clement Lounsberry to come to Bismarck and establish The Bismarck Tribune.
Hannifin Avenue is named in his honor.