The House Today
The Ellwood House property today consists of about 8.5 acres, which includes the wooded area to the North of the mansion. The original Ellwood estate totaled more than 1,000 acres, extending north and west of its current boundaries. Much of the property was pasture and farm land devoted to the Ellwood stock farm "Ellwood Green" for the breeding of Percheron draft horses.

The Ellwood House has undergone two major transformations since the time of its original construction in 1879. As a result, there are three periods which need to be explained in order to understand the development of the house. Each of these periods can be related to both the exterior and the interior of the mansion.

The Original House ~ 1879-1898
The architect of Ellwood House was George O. Garnsey of Chicago, who built other stately homes and churches in DeKalb and Sycamore. Construction began in April and the home was occupied by the family in November 1879. The original cost is given in the newspapers of the time at between $40,000 and $50,000.

In typical Victorian fashion, the house combined elements of several historical styles. The mansard roof is still one of the most prominent features today.

Other elements include Gothic columns, pitched gables and cast-iron roof cresting with its trefoil design.

Changes from 1898-1910
At the end of the 19th century, the Ellwood House was updated to reflect a newly popular style: the Georgian or Colonial Revival which looked back to 18th century English and American architecture for inspiration. Classical elements submerged many of the earlier Gothic features. On the exterior, the most prominent changes was the addition of the portico and portecochere or carriage entrance. The entrance was given Georgian features, including a fan-shaped window over the doorway. A Palladian window with a large shell motif highlighted the second floor and a classical cornice replaced the earlier bracketed one. Georgian details and proportions were given to the dormers. The dining room was also enlarged by the addition of a semicircular bay matching the portico in design.

The Final Remodeling
In 1911 Perry Ellwood and his wife May began a period of construction which brought the mansion to the home we know today. The most significant changes were the addition of the terrace on the south side of the house, the addition of the sunroom wing and the relocation of the porte-cochere to the north side of the portico.

The entire south side of the mansion was "squared up" to accommodate this work. The sunroom wing was a novel addition in the Arts & Craft style contrasting with the rest of the mansion.

Isaac Leonard Ellwood was born in Salt Springville, New York on August 3, 1833. His parents were people of modest means. Already ambitious as a young man, he drove a mule team on the Erie Canal. In 1851 he made his way west to seek his fortune in the gold fields of California. He clerked in a hardware store in Sacramento and saved his earnings hoping to establish his own business.

In 1855, Ellwood made his way to DeKalb County, Illinois, where several of his brothers had already settled. Here he found work on the large farm of William Miller near Kingston. Isaac married Miller’s daughter Harriet in 1859 and soon established a hardware store on Main Street in DeKalb.

Keenly aware of the needs of farmers for a cheap durable fencing material through his hardware business, Ellwood began to tinker with ways to improve fencing.

In 1874 he abandoned his own idea and purchased a one-half interest in DeKalb farmer Joseph Glidden’s barbed wire patent for $265. The two soon formed a partnership and established the world’s first barbed wire factory. By 1879, fifty million pounds of barbed wire were being produced annually and Ellwood was well on his way to becoming one of the wealthiest men in Illinois. This wealth enabled him to build a palatial home for his family on a large property at the edge of DeKalb.