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 States 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. Marys. 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.
The present couthouse was completed for occupancy in 1891 at a total cost of $106,951.46 for building and equipment.
On November 6, 1849, the electorate voted for township organization and the Commissioner Court appointed three men to divide the county into towns. Their report, filed February 5, 1850 named nineteen townships, comprising an area of 757 sq. mi. The first special meeting of the Board of Supervisors was held November 11, 1850.
In 1972, in compliance with the State Legislatures decision on reapportionment, Ogle County held its first election to elect County Board members.
The county was divided into four districts, with six members from each district. This replaced the system whereby the township supervisors served as the County Board. A supervisor may also be a County Board member but not necessarily.
The 1998 estimated census shows a County population of 50,511. There are presently approximately 30,539 registered voters.
Three State parks are located in Ogle County.
Weld Park, located in Marion Township, was given to the County to maintain as a County Park. Sinnissippi Farms southeast of Oregon in Oregon/Nashua Township is the home of former Governor Frank O. Lowden.
The Lowden Boy Scout Camp and Camp Medill McCormick for Girl Scouts are located in Ogle County. In 1962 the Ogle County Historical Society opened a museum in the Ruby Nash home in Oregon. This is open to the public on week ends during the summer months.
Renovation of the interior of the Courthouse was completed in 1984 at a cost of $1,500,000.00.