The house was originally part of 1,000 acres (4.0 km2) which included a large stable complex known as "Ellwood Green."

[2] The original Ellwood House had a number of elements common to Victorian designed homes and combined several styles.

In addition, the home still incorporates Gothic columns, pitched gables, and a cast iron roof cresting with a trefoil design.

The changes, commissioned by Isaac Ellwood, were meant to reflect more popular architectural styles including the Georgian and Colonial Revival.

[2] Inside the home, the dining room was enlarged with the addition of the semicircular bay on the mansion's north facade.

[4] The biggest changes were the addition of the terrace on the home's south face, a sunroom wing, and the relocation of the porte-cochere to the north side of the portico.

[5] The three-story brick house includes a full elevated basement and a mansard roof with steeply pitched gabled dormers.

Projecting from the roofline are plain corbeled chimneys and iron gillwork, the original roofing material was slate.

The original windows were all double-hung and of modest size, occurring both singly and in pairs while showing a variety of lintel designs.

In the southeast corner of the house was a full three-story projecting tower set at a 45° angle to the rest of the front facade.

[6] Isaac Ellwood's 1898-1899 renovations were superficial, especially when compared to the alterations his son made to the original design a decade later.

The windows over that portico were replaced with a heavy double door that opened onto the roof over the veranda, which had been built over the entire front of the house.

[6] The general layout of the home's interior has remained basically the same throughout the remodelings; the rooms on each floor are accessed via a large central hallway which ends in an elegant rotunda.

Prominent among the library's features is a carved Italian marble mantle with a large gilt mirror hung above it.

[3] The dining room's underwent an extensive remodel in 1898 because of Ellwood's rise to national prominence through his barbed wire partnership with Joseph Glidden.

Beyond the addition, the room was refurnished and redecorated to reflect the Georgian Revival alterations that were occurring on the home's exterior.

Elements of Georgian Revival architecture that were incorporated into the Ellwood dining room remodel include, mahogany paneling with dentil molding around the windows and doors, a cornice with Classical details, and brackets.

[3] Almost all of the dining room's 1898 furniture and woodwork was custom made by Tobey & Company of Chicago and each piece is affixed with a dated brass plate.

The dining room's smaller table, situated within the bay addition, was used for Ellwood family breakfasts.

[7] The living room features a "pargework" ceiling constructed of molded plaster and designed with a geometric theme.

The museum offers tours seasonally beginning in late spring and ending after the annual holiday celebration in December.

The DeKalb Area Garden Club hosts an annual Flower Show, community members hold weddings in the garden or visitors center, and the Ellwood House Association holds an annual Art Show, Ice Cream Social, and other events.

[9] The water tower is the only surviving structure from what was once a large horse stable facility owned by Isaac Ellwood.

The building is sheathed in stucco and presently houses a collection of antique carriages and sleighs as well as a barbed wire history museum.

[9] The Museum House is cast in Classical Revival style and was the last outbuilding constructed for Isaac Ellwood on the property.

Today the Museum House's exterior appears much the same as it did when it was newly constructed but for many years the structure was badly deteriorated.

Eventually, the Little House wound up at the property of Mr. and Mrs. Burt Oderkirk, on Annie Glidden Road, where it again served as a playhouse for the couple's children.

[10] The house is most significant for its connection to Isaac Ellwood, who has been given credit, in part, for Joseph Glidden's invention of barbed wire.

[15] The Ellwood House, including the four contributing properties on its 8.2-acre (33,000 m2) site, were added to the U.S. National Register of Historic Places on June 13, 1975.