Peacock Brewery, also known at times as the Rockford Brewing Company and the Rock River Brewing Company, is a historic pair of buildings on the east side of the Rock River in Rockford, Illinois, United States.

Peacock had learned the brewing trade in England before working in Chicago's Lill & Diversey brewery.

Peacock ground malt in a coffee mill, brewed it in a wash boilers, and delivered his product to customers via wheelbarrow.

With the connection of the Galena and Chicago Union Railroad to Rockford in 1852, Peacock was ready to serve the droves of immigrants that followed.

[1] John Petritz had moved out west to Montana in the 1880s and made a fortune in liquor production and distribution.

With the Peacock Brewery under his ownership, he hired St. Louis architects Widmann, Walsh & Boisscher to design a large, modern brewhouse.

John V. Petritz, his son Frank, and manager Earl Blewfeld were arrested that year for the violations.

Petritz was forced to pay a combined $15,000 to the city and county in a settlement for 1,250 violations of liquor laws.