The likes of Theodore Roosevelt and Jane Addams visited Ellwood House when it was the primary residence for one of the region’s wealthiest families.

Officially, to qualify as a mansion, a house needs 20 rooms. By one count, Ellwood House has 33 rooms, six bathrooms, two wine cellars, 13 hallways and two staircases, according to Steve Bigolin, author of “A Journey Through DeKalb.”

Gerald Brauer, Ellwood House Executive Director, said 20 of those rooms, spread out over four floors, are open to the public during tours.

The Ellwood House, 509 N. First St., was erected in 1879 by Isaac Leonard Ellwood (1833-1910), one of the three inventors of barbed wire profiled in Dr. Jeffrey Chown’s documentary “Barbed Wire Pioneers.”

Ellwood, a New York native, owned a hardware store in DeKalb at the time he, Joseph Glidden and Jacob Haish all viewed Henry Rose’s design for spiked fences at the 1873 DeKalb County Fair. It was there that they were inspired to develop improvements of the Rose design.

At the urging of his wife, Harriet, Ellwood decided to abandon his own design for barbed wire and buy a half interest in Glidden’s patent for $265 in 1874.

Together, the two men formed the Barb Fence Company and opened the world’s first barbed wire factory, though in 1876 Glidden sold his remaining interest.

By 1879, Isaac Ellwood & Company was producing 50 million pounds of barbed wire annually. The consequent wealth allowed Ellwood to build this palace on 1,100 acres of property, though only eight acres were left when the house became a museum.

Construction of the house cost between $40,000 and $50,000, using a design by Chicago architect George O. Garnsey.

The library, dining room and greenhouse are the main attractions for tourists on the ground floor. The family bedrooms are on the second floor, and the dancing room and servants’ quarters occupy the third. The highlight of the house in many respects, though, is the three-story rear staircase under the rotunda.

The house was remodeled in 1888, and the kitchen was transferred from the basement up to the first floor.

In 1910, Isaac passed away and the house was inherited by his second son Perry Ellwood. Perry and May Ellwood remodeled the house again in 1911, adding the terrace on the south side of the house and the Arts & Crafts-style sunroom wing and relocating the porte-cohere to the north side of the portico.

Perry and May’s three children Patience, Jack and Issac Leonard II donated the property to the DeKalb Park District at the urging of NIU art professor Jack Arends after the death of Perry’s widow.

“Patience was the most interested of Perry’s children in preserving the family legacy, but if Dr. Arends hadn’t acted, Ellwood House may have simply been sold and torn down by the next owner after May died,” Brauer said.

The museum was opened to the public in 1967 and the Ellwood House Association, the non-profit organization that administers the museum, was founded by the volunteers who gave the first tours. Brauer is celebrating his 20th anniversary as executive director of the group this year.

Membership fees in the Ellwood House Association range from $20 for individuals to $30 for families. Members receive free admission for tours and a subscription to a quarterly newsletter called The Ellwood House Herald.

Membership funds and revenues from tours go toward repairs, such as two years ago when the Second Empire-style roof was repaired at a cost of $120,000, Brauer added.

Donna M. Gable, Coordinator of Volunteers & Visitor Services, has 20 volunteer guides at present, but always is looking for more.

Guided tours are given at 1 and 3 p.m. Tuesday through Friday, and at 1, 2 and 3 p.m. Saturday and Sunday. It is free to explore the Ellwood House Visitor Center and $6 for guided tours of the house. NIU students can get in for $5, children 6-14 are $1 and children under 6 are free.

There is a free art fair that attracts artists from all over the Midwest every first Sunday in July and a free Ice Cream Social every first Sunday in August.

For the first two weekends in December, the house is decorated for Christmas, with a different group decorating each room.

The museum is closed annually between the second week of December and the end of February.