Illinois Brewing Co.
Independent Milwaukee Brewery
International Breweries, Inc.
Iron Brew
Iron City Brewery
Jackson Brewing Co.
Jacob Best Light
Jacob Leinenkugel Brewing Co.
Jacob Ruppert (Inc.)
Jacob Schmidt Brewing Co.
Jax Beer
John Hauenstein Co.
Joliet Citizens Brewing Co.
Jos. Huber Brewing Co.
Joseph Schlitz Brewing Co.
JR Beer
Jung (William G. Jung) Brewing Co.
Jung Pilsener Beer

Kaliber by Guinness (Ireland)
Kato Premium Beer
Kiewel Brewing Co.
Kiewel's Beer
Kiewel's White Seal

Kingsbury (Pale) Beer
Kingsbury Breweries Co.

Knickerbocker Beer
Koch (Fred Koch) Brewery
Koch's Beer

Krantz Brewing Corp.
LaCrosse Breweries, Inc.
Lakefront Brewery, Inc.
Lancers Beer
Latrobe Brewing Co.
Leinenkugel (Jacob Leinenkugel) Brewing Co.
Leinenkugel's Beer

Lemp Beer
Lemp (Wm. J. Lemp) Brewing Co.

Libertyville Brewing Co. (Mickey Finn's Brewery)
Lite Beer from Miller 
Lone Star Beer
Lone Star Brewing Co.
updated August, 2016
Long Island Brewing Co. 
Long Valley Pub & Brewery
Louis Ziegler Brewing Co.
Lowery (A.H. Lowery) Co.
Lucky Breweries, Inc.
Lucky Draft
Lucky Lager