Knollwood is an unincorporated community and census-designated place (CDP) in Lake County, Illinois, United States.

[6] In 1923, Knollwood Farm was purchased by a group of wealthy Chicago businessmen (including Samuel Insull, Robert P. Lamont, Nathan William MacChesney and Thomas E. Wilson), who wished to turn the land into a country club.

Mr. Grum, a former full-time member of the Lake Forest Fire Department who retired as deputy chief,[10] and Dan Rogers led the efforts to dissolve the district.

Despite a referendum that required trustees to be elected, rather than appointed, and a majority of residents opposing his re-appointment,[11] Rogers was re-appointed to his position, and along with Trustee Grum cast the voted needed to approve an Inter-Governmental Agreement that ended Knollwood FD operations on August 31, 2018.

According to the U.S. Census Bureau, the Knollwood CDP has an area of 0.6 square miles (1.6 km2), all of it land.

U.S. Route 41 passes through the eastern part of Knollwood, though several sections fall within the boundaries of Lake Bluff.

Knollwood was served by the Mundelein Branch of the Chicago, North Shore and Milwaukee interurban railroad until its abandonment on January 21, 1963.

[19] Since then, Knollwood has not been served by passenger rail, though the Lake Bluff Metra Station is located nearby.

This line was built in the late 1880s as part of the short-lived Waukegan and Southwestern Railway, before it was acquired by the Elgin, Joliet and Eastern in 1891.