DULUTH — More than three years and $165 million later, the once polluted U.S. Steel grounds along the St. Louis River are nearly set to welcome visitors.

Open next summer, the 92 acres of permanently protected green space will include a 2-mile trail extension along the water, a 1-mile wheelchair-accessible loop circling a peninsula, bridges and interpretive signs honoring the Anishinaabe's ties with the river.

"What was once a really important thriving industrial site, had, of course, the impact of ecological degradation and pollution," Duluth Mayor Emily Larson said during a tour of the area Wednesday via the Lake Superior & Mississippi Railroad.

"And with U.S. Steel and the [Environmental Protection Agency], we are now able to re-envision something so different here — very healthy — that is still in keeping with the heritage of this community, and our land and our people," she said. "This is a total changed experience."

The Superfund site in the Morgan Park neighborhood was home to a coking and mill operation that closed in 1981, and the riverfront there, overgrown with invasive plants and choked by toxic chemicals, has been closed to the public for decades.

Federal, state, local and tribal efforts to clean up the river and remove it from a national list of polluted waterways, designated as Areas of Concern, have been ongoing for more than 30 years. The U.S. Steel Duluth Works site is next to the wide Spirit Lake portion of the river and was the largest and most complex contamination removal project involved in those efforts.

While mill operations "fed many families over the decades," Mark Rupnow of U.S. Steel said, "we're happy to see it get to the state it's in today."

Nearly 140 acres of cleaned riverbed now hold a shallow sheltered bay for fish and other wildlife, the area newly home to more than 360,000 aquatic plants that were grown onsite in a nursery.

The Environmental Protection Agency's Mark Loomis said visitors should give the fragile vegetation on land and in the water time to become established. The waterfront will eventually be filled by native marshes, and not the sandy bottom it has now. Shrubs and prairie grasses cover the landscape, and water lilies and reeds will grow, he said, calling the transformation "natural space restoration," rather than an area for swimming.

However, he said, anglers and those paddling the river's nationally designated water trail will find varying water depths with new shoals and channels.

The St. Louis River Alliance is reconnecting waterfront neighborhoods to the river they were so long isolated from. Foraging, birding and paddling events are planned, with preference given to nearby residents, said Kris Eilers, leader of the Alliance.

Restoration is critical, she said, but so is access to the estuary.

"It's amazing to see this getting done after so many decades," Eilers said.

The Waabizheshikana Trail extension runs along the Lake Superior & Mississippi tourist railroad, which paused operations during the project and restarted this summer.

In 2022, the Environmental Protection Agency announced $113 million for three highly contaminated sites in the river, including the Spirit Lake area. It paid for a major chunk of the work necessary to remove its federal Area of Concern designation.

U.S. Steel is responsible for 51% of the $165 million, with federal funds covering the rest. The city has also invested in recreational improvements along the river.