A handful of listings from from Brewers Digest "Buyers' Guide and Directory, 1977," a directory listing every brewery in every state.

Breweries located in:

California:
Miller Brewing Co.
Anheuser-Busch, Inc.
Pabst Brewing Co.
General Brewing Co.
Falstaff Brewing Corp.
Steam Beer Brewing Co.
Jos. Schlitz Brewing Co.
Note: New Albion opened for business in July 1977, but the folks at Brewers Digest weren't yet aware of its existence

Colorado:
Adolph Coors. Co.

Oregon:
Blitz-Weinhard Co., Inc.

Pennsylvania:
Horlacher Brewing Co.
F. & M. Schafer Brewing Co.
Erie Brewing Co.
Latrobe Brewing Co.
Henry F. Ortlieb Brewing Co.
C. Schmidt & Sons, Inc.
Pittsburgh Brewing Co.
D. G. Yuengling & Son., Inc.
Straub Brewery
Jones Brewing Co.
The Lion, Inc. - Gibbons/Stegmaier Brewery

Wisconsin:
Jacob Leinenkugel Brewing Co.
Walter Brewing Co.
G. Heileman Brewing Co., Inc.
Miller Brewing Co.
Pabst Brewing Co.
Jos. Schlitz Brewing Co.
Jos. Huber Brewing Co.
Stevens Point Beverage Co.