St. Paul-based Summit Brewing Co. has ended distribution of its craft beers in six more states, leaving just five in the Upper Midwest where connoisseurs will be able to buy the brewery’s seven year-round beers as well as its many seasonal and limited-release beers.

Officials last week announced the move to stop distribution in Pennsylvania, Ohio, Illinois, Indiana, Nebraska and Michigan in a posting on its website and Facebook page.

In what it called a “difficult decision,” the company cited challenges in getting its product to retailers due to changes in the industry and the need to meet rising demand in its core Midwestern market.

“We’ve been invited into your homes, businesses and refrigerators, and we’ve been fortunate to make friends and fans out of folks across the country. It’s been a great honor to share our beer with you all,” part of the announcement reads. “We are sorry to leave your area and look forward to returning in the future.”

Summit spokesman Brendan Kennealy declined to provide additional information.

Summit was started 31 years ago by home-brewer Mark Stutrud. Over the past three decades, Summit has grown from a tiny operation that began in a nondescript building on University Avenue to a multifaceted operation on a 6-acre campus in a redeveloped St. Paul industrial park off Montreal Avenue.

Last year Summit reported revenue of $30 million from its 129,000 barrels of beer.

The company, which employs more than 100 people, has seen slower growth in recent years as the number of craft breweries in Minnesota — its primary market — has skyrocketed.

At one time, the nation’s 29th-largest craft brewer and second largest brewery in Minnesota shipped its suds to 17 states and grew a loyal fan base.

In recent years that shrunk to 11 and now down to five. More than 75 percent of sales are in Minnesota and the rest from surrounding states. Summit will continue distribution in Iowa, Wisconsin, North Dakota, South Dakota, as well as its home state.

“Very sad news that you’ll be leaving Pennsylvania,” wrote Steve Swiggum in a Facebook posting. “My grandparents live off West 7th, so drinking Summit always brings Minnesota to my house. You gotta do what you gotta do though, hope you’ll come back to the Keystone State soon! Cheers!”