The O'Brien Barn is located on O'Brien Farms which is a 6th generation family farm located 4 miles southwest of Oregon, WI.. The farm was first started by Louis O'Brien in 1909 descendant of Cornelius O'Brien who came from Ireland in 1830, and then to Wisconsin 1853. The O'Brien Barn was erected in 1938 by Louis O'Brien and son Maurice.
Over the years the Barn was home to many generations of horses (back when horsepower meant actual number of horses) cattle, cats, barn swallows, and raccoons. Maurice O'Brien, (son of Louis) added 40 feet to the barn in the 30's after a tornado ripped off the end. Dan and Mark O'Brien (Maurice's sons and current owners) spent many years milking and decided to hang up their stools in 1999. After many years of collecting dust and used for intermittent storage, Connie O'Brien, Dan's daughter, and soon to be husband, Dale Nelson talked Dan and Mark into letting them cleanup the place for their wedding in 2004. It took a year and a half of renovating .
The Barn is approximately 90 x 40 feet. It has two levels, the upstairs being a large hay mow with a stage for music and downstairs made up is cement and stone walls where they used to milk. Two sets of stairs have been created to the hay mound area. The milk house has been converted to restrooms.