What is now Ogle County was once a part of the Northwest Territory.
In 1809 the Territory of Illinois was formed and included Wisconsin and Peninsular Michigan. In 1818 Illinois, in its present boundaries, became the 21st State to join the Union.
Ogle County was formed in 1836 from a part of Jo Daviess County.
The name, Ogle, was suggested by Thos. Ford in memory of Capt. Joseph Ogle who distinguished himself for his courage and coolness in the early days of the State’s history.
The first session of the Ogle County Commissioner’ Court was held at Oregon on January 3, 1837, and Oregon was chosen to be the County Seat.
Because there was so much dissension, efforts were made to divide the County and on February 27, 1839, the Legislature approved an act creating Lee County out of the southern half of Ogle county, with Dixon as its County Seat.
In December 1839, the County Board ordered the town of Oregon to be called Florence; in 1843, however, it was renamed Oregon.
Names of other towns were once different than those used today. Rochelle was once called Lane; Byron, Bloomingville; Polo, Buffalo Grove and St. Mary’s. Plans for a courthouse were adopted on December 4, 1838, and in 1841 the building was completed – only to be burned before it could be occupied.