Cortland Township, DeKalb County, Illinois

Cortland is an incorporated town in DeKalb County, Illinois, United States. The population was 4,398 at the 2020 Census. It was previously 4,270 at the 2010 census, up from 2,066 in 2000. Because of its status as an incorporated town, Cortland has adopted the slogan, "The Third Largest Town in Illinois". Only the towns of Cicero and Normal are larger, in terms of population. Most municipalities in Illinois are defined as "cities" or "villages."

DeKalb Taylor Municipal Airport (ICAO: KDKB, FAA LID: DKB), which opened in April 1944, is a general aviation airport and is situated on 920 acres (3.7 km2) at an elevation of 914 ft (279 m) and located two miles (3.2 km) east of DeKalb, Illinois, United States. DeKalb Taylor Municipal Airport is located approximately 60 mi (97 km) west of Chicago. The airport is open 24 hours a day and is owned by the city of DeKalb.

The Sycamore Historic District is a meandering area encompassing 99 acres (400,000 m2) of the land in and around the downtown of the DeKalb County, Illinois county seat, Sycamore. The area includes historic buildings and a number of historical and Victorian homes. Some significant structures are among those located within the Historic District including the DeKalb County Courthouse and the Sycamore Public Library. The district has been listed on the National Register of Historic Places since May 2, 1978. There are over 200 properties within the irregular boundaries of the Sycamore Historic District. Of those, 187 are considered contributing properties to the historic district, and 22 are non-contributing. Of all of the district's homes and buildings 75% fit within the historic district concept. Some of the major structures include several prominent Queen Anne style mansions, the Sycamore library, the DeKalb County Courthouse, and dozens of mid- to late 19th-century houses.

The Sycamore Public Library, in Sycamore, Illinois, was erected in 1905 in the former location of Mansion House, Sycamore's oldest structure. Construction began in May of that year and the library officially opened to the public on Thanksgiving Day, 1905. The library joined the National Register of Historic Places in May 1978 with the rest of the Sycamore Historic District. The library still operates, as of 2019, as the Sycamore library. The library was erected with the help of a $10,000 grant from Andrew Carnegie in 1905.

The DeKalb County Courthouse is located in the county seat of DeKalb County, Illinois, U.S., the city of Sycamore. The Classical Revival structure sits on a square facing Illinois Route 64 as it passes through the city. The current courthouse was constructed in 1905 amid controversy over where the courthouse and thus, ultimately, the county seat would be located. The current building is the third structure to bear the name "DeKalb County Courthouse." DeKalb County's Courthouse still serves as the county's primary judicial center and is a contributing property to the Sycamore Historic District. The district joined the National Register of Historic Places in 1978. As the county's primary courthouse for over 100 years, the site has been host to many trials, including prominent murder cases. The building is cast in the Classical Revival architectural style and contains elements common to that style. Stained glass, columns and a pediment are among the more noticeable features at a glance. The rear facade of the building is designed to resemble a temple and also features stained glass windows. A stone porte-cochere covers the rear driveway. Inside the building's third floor courtroom is more stained glass, in the form of a skylight. During the early 1980s the made-for-television movie Will: G. Gordon Liddy filmed scenes in the DeKalb County Courthouse's courtroom.

The Charles O. Boynton Carriage House is a prominent structure in the Sycamore Historic District, located in Sycamore, Illinois. The Sycamore Historic District was added to the National Register of Historic Places in 1978. The Carriage House is considered one of more than 150 contributing properties to the overall historic integrity of the district.

The Carlos Lattin House was built by Sycamore, Illinois' first permanent settler, Carlos Lattin. It lies within the boundaries of the Sycamore Historic District and is listed as one of the contributing structures in the district. The Sycamore Historic District was added to the National Register of Historic Places in 1978.

The George's Block, once known as the James Block, is a 19th-century structure located in Sycamore, Illinois, along Illinois Route 64 (State Street) as it passes through the DeKalb County seat. The Block is part of the Sycamore Historic District and as such is listed on the National Register of Historic Places. The district joined the Register in May 1978. The building dates from 1857 when it was owned by Daniel P. James but by the 1860s the building has become known as George's Block.

The Peter Johnsen Rooming House is an historic building near downtown Sycamore, Illinois. The red brick structure stands in the 100 block of South Main Street and is considered a contributing structure to the overall historic integrity of the Sycamore Historic District. The district was added to the National Register of Historic Places in May 1978.

The William W. Marsh House in Sycamore, Illinois, the county seat of DeKalb County, has been listed on the National Register of Historic Places since 1978. The 1873 house was home to William W. Marsh, an inventor and is located along Illinois Route 64 as it passes through Sycamore. The Marsh House was built in the Italianate style and contains distinctive Italianate elements such as a cupola, a low pitched roof and eaves supported by corbels.

The D. B. James House is located in Sycamore, Illinois and is part of the Sycamore Historic District. The district was entered on the National Register of Historic Places in 1978. The James House is one of 226 properties located within the district boundaries. It stands on the corner of Exchange and Main Streets behind the DeKalb County Courthouse.

The Row Houses in Sycamore, Illinois are a small collection of historic terraced homes near the city's downtown. The building is considered by the National Register of Historic Places to be a contributing structure to the overall historic nature of the Sycamore Historic District. The district was added to the Register in May 1978. The buildings stand on the corner of Elm and California Streets in Sycamore.