Encouraged by two previous experiments, the National Park Service now plans a six-month presence on the Minnesota side of the St. Croix River that will begin in May.

The agency will post a ranger at Arcola Mills, an early lumber mill about six miles north of Stillwater. Volunteers will be recruited to staff a visitor center at the eight-bedroom Mower-Van Meier mansion, a Greek Revival house built in 1847, to share the history of the village via interpretive displays and storytelling.

To the Park Service, location is everything. The St. Croix National Scenic Riverway is a national park encompassing nearly 98,000 acres, but most Minnesota residents might not know that.

"I do think that we realize that one of our largest audiences is the Twin Cities," said Jonathan Moore, the ranger who will work out of Arcola Mills this summer. "That's very much still something that we're working on ... sharing with people that they have a national park right in their back yard. It exists as one of the 400 units of the National Park Service for a reason. It's one of those special places."

Arcola Mills, north of Stillwater and south of Marine on St. Croix, is a 55-acre property managed by a foundation. The site is possibly the oldest attraction on the St. Croix River. It's a step back in time to when the pioneering Mower brothers, John and Martin, built a riverside sawmill and a village to sustain it.

"We're anxious to conduct the full experiment to see how it works during an entire summer season," said Ray Marshall, a Lake Elmo attorney and board chairman of the Arcola Mills Historic Foundation.

The National Park Service first sampled the potential of the Arcola Mills site in October 2011, drawing 4,077 visitors. A similar undertaking in September and October of last year — nearly double the number of days — attracted 4,040 people.

"Our previous experiments showed strong interest in a visitor center in this area during the fall color season," Moore said. "We are hoping that a third experiment would show what kind of interest and visitation there would be for such a center in the warmer summer months."

Acquainting the public with the riverway has been a challenge for the park service, which has its headquarters on the Wisconsin side of the river in St. Croix Falls. The federal agency has no permanent presence on the busier Minnesota side, although it staffed an office in Stillwater in the 1990s.

Visitors in the past two NPS experiments were surprised to learn of Arcola Mills' history and the presence of a national park, said volunteer Dian Gardner of Shoreview.

"They just thought it was a scenic drive and a pretty waterway. Many of them didn't know what they were going to see," she said. "The word is starting to spread that this is an interesting spot and a beautiful view of the river."

Gardner and her husband, Jim, have volunteered as many as 16 hours a week and oversee volunteer training. Last fall, 52 volunteers donated 967 hours to the effort.

The May Township board, at a recent meeting, approved a May-through-October experiment for this year. Further approvals would be needed if the Park Service wants a visitor center beyond 2013, Moore said.

A spring-summer-autumn experiment at Arcola Mills would cost about $45,000, mostly for staffing. The Park Service doesn't pay rent to Arcola Mills, a foundation that incorporated in 1992 after the death of previous owner Katharine Van Meier.

The foundation has struggled financially over the years for lack of benefactors, Marshall said. Some money is raised through events like business retreats and wedding rentals at the mansion, but an ongoing Park Service presence will require more income, he said.

"We regard our partnership with the National Park Service to be an important one," Marshall said. "We're hoping that this isn't the end of the line. We hope to see this work. Going forward it's going to be very difficult without a funding source."

Moore said the Arcola location allows the Park Service to display its familiar "arrowhead" signage on Hwy. 95 to encourage people to stop at the visitor center.

Last fall, the largest number of visitors came from Stillwater and St. Paul, followed in order by Minneapolis, Marine on St. Croix, Woodbury, St. Croix Falls, White Bear Lake and Lake Elmo. But the visitor log showed 39 states were represented, and so were 16 foreign countries including Australia, Germany, Puerto Rico and Vietnam.

Kevin Giles • 651-925-5037