What is believed to be an original map of Lake Geneva — found recently inside a historic lakefront mansion — now offers the public a rare glimpse of the city in its earliest origins.

The map from the early 1840s is part of Geneva Lake Museum’s new exhibit “Mapping the Past,” which opened May 24 and is a permanent new attraction in the museum.

The exhibit features about 30 maps of Lake Geneva and the surrounding area, including the original map showing Lake Geneva’s layout just after pioneers incorporated the new municipality in 1836.

James Davis, a docent for Geneva Lake Museum, said the pioneer-era map is an important find.

“This is indeed a rarity,” Davis said. “This is what is going to blow everybody’s mind.”

The map was donated about six months ago by representatives from Black Point Estate, itself a museum created from one of the Lake Geneva’s early lakeshore mansions.

David Desimone, site coordinator at Black Point Estate, said the map was located inside an non-operational elevator at the estate, which is a Queen Anne Victorian-style home built in 1888.

Desimone said he decided to donate the map to the Geneva Lake Museum because he felt it would be a more appropriate location for the artifact to be displayed for the public.

“It made sense for the museum to have it, because it is a story they can tell,” he said.

The map was prepared by Thomas McKaig, described as one of the original surveyors of Lake Geneva.

Desimone said he believes the map was obtained by Otto Schmidt, who lived at Black Point with his wife, Emma Seipp, from the 1920s through the 1940s. Many generations of the Seipp family lived at the estate before the property was converted into a museum.

Desimone said Otto Schmidt was the family member “who we know of who collected stuff.”

What remains a mystery is where or when Otto Schmidt would have obtained the historic artifact — and whether other copies of the rare map are in existence anywhere.

“Everyone who I’ve talked to has said they have never seen one,” Desimone said.

Black Point Estate also has a map from the 1930s depicting a train route between Lake Geneva and Chicago. That map will remain part of the historic collection on display at Black Point.

“That is more of our story,” Desimone said. “That’s where our story picks up.”

At the Geneva Lake Museum, the 1840s map is displayed inside a glass case along with the very same surveying and drawing equipment that, according to officials, McKaig used to produce the map.

Davis said the drawing and surveying equipment was donated to the museum several years ago.

“We had the tools, but we didn’t have any connection,” Davis said.

Besides the original Geneva Lake map, the new exhibit features plat maps, plot maps, fishing maps, railroad line maps, lake depth maps, snowmobile route maps, street maps and estate maps.

In addition to Lake Geneva, the maps show various depictions of Fontana, Williams Bay, the town of Linn, the town Walworth and other surrounding communities.

“Map lovers will love it,” museum director Janet Ewing said.

Another popular display involves a 1979 map listing businesses that were located in Lake Geneva at the time of Jimmy Carter, disco music and the emerging 1980s decade.

“It’s a fun map,” Davis said. “It’s got a lot of memories.”

The majority of the maps in the exhibit have been donated by Edward Weed of the town of Linn.

Weed said he still has about 60 maps in his private collection, which is displayed on the walls of his home. Weed said he has been collecting maps of the Lake Geneva area since the 1950s.

“I would stumble upon one map, then I would stumble upon another,” he said. “They would just find a way into my home.”

Weed said he would donate more maps, if the museum needed them.

“I think they have taken pride in the exhibit,” he said. “They have done a splendid job.”

The map exhibit is open to all paid visitors at the museum.

Ewing said patrons also can purchase printed copies of the maps, included a scaled-down copy of the pioneer map.

The exhibit also features display cases with items from mansions and estates in the area, including postcards and photographs, and a display highlighting Yerkes Observatory and the Riviera.

Davis said the museum plans to rotate maps and items in and out of the exhibit on a semi-regular basis. The museum also plans to include a photographic slideshow of the different Lake Geneva estates.

Museum officials had been working on the map exhibit for about a year.

Officials had originally planned to make it a temporary exhibit, but as they collected more items, they decided to make it a permanent exhibit.

“The more we got into it, we just got working and working,” Davis said.