The space once occupied by Walnut Brewery in downtown Boulder is up for sale.The property at 1123 Walnut St., measuring about 7,000 square feet, has a price of $5 million, said Geoffrey Keys, president of Keys Commercial Real Estate, the listing agency. “We’ve had a lot of interest from many people in restaurant and retail business.”

The building, which was built in 1900, was used as a restaurant before his client acquired it in 1989 and started the original brew pub concept Walnut Brewery a year later, Keys said. The brewery closed in 2017, and was replaced by Boulder Beer, which transformed it into Squared Pizza + Beer, a Detroit-style pizza restaurant in 2018. Squared Pizza closed in December after a short run.

The property, which has 50 feet of retail frontage, has remained vacant since the closing of Squared Pizza, Keys said. It potentially could be developed as a mixed-use concept with office space on the second floor, and retail on the ground floor, he said.