Brewery (Number of groups) (Click a Brewer to view coasters)	Sort by code	Sort by Production Dates *RED = CLOSED*	Sort by city	Sort by count
O'Donnell & Duer	IL-ODON	1892-1904	Chicago	4
O'Fallon Brewing Co	IL-OFALL	1992-1993	O'Fallon	1
O'Grady's Brewery	IL-OGRAD	1996-2001	Arlington Heights	2
O'Griff's Grill and Brewhouse	IL-OGR	2004-2019	Quincy	2
Oak Park Brewing Co.	IL-OAK	2016-2021	Oak Park	3
Obed & Isaac's Microbrewery & Eatery	IL-OBED	2012-	Springfield	17
Obscurity Brewing	IL-OBSC	2018	Elburn	16
Off Color Brewing	IL-OFF	2016-	Chicago	55
Off-Kilter Brewing	IL-OFFK	2016 - 2022	South Beloit	8
Ogle County Brewery	IL-OGLE	2020-	Oregon	2
Old Abbey Brewing Co	IL-ABB	1936-1941	Chicago	13
Old Bakery Beer Company	IL-OLDB	2014-	Alton	16
Old Herald Brewery & Distillery	IL-OLDH	2019	Collinsville	7
Old Irving Brewing Co.	IL-OLDI	2015-	Chicago	16
Old Town Abbey Ales	IL-OLDT	2014-	Chicago	1
On Tour Brewing Company	IL-ONTO	2017	Chicago	10
One Allegiance Brewing	IL-ONEA	2020-	Chicago Ridge	8
One Lake Brewing	IL-ONEL	2019	Oak Park	7
One Trick Pony Brewing	IL-OTP	2012-2024	Lansing	19
Only Child Brewing	IL-ONLY	2013-2022	Gurnee	7
Open Outcry Brewing Co.	IL-OPEN	2017	Chicago	6
Opera House Brewing Company	IL-OPER	2018-	Hillsboro	2
Orkenoy Brewing (Ørkenoy)	IL-ORKN	2020-	Chicago	3
Oswego Brewing Co.	IL-OSWE	2018-2023	Oswego	6
Ottawa Brewing Assoc.	IL-OTTA	1906-1920	Ottawa	9
Illinois brewers with coasters:				25
Alternate brewer referencess:
total record count:				25