It was named for Dr. Hugh J. Glenn, who purchased 8,000 acres (32.4 km2) in the northeast end of Rancho Jacinto in 1867.

He became the largest wheat farmer in the state during his lifetime and a man of great prominence in political and commercial life in California.

[10] The 2010 United States census reported that Glenn County had a population of 28,122.

Glenn is a strongly Republican county in Presidential and congressional elections.

Glenn County is split between California's 1st and 3rd congressional districts, represented by Doug LaMalfa (R–Oroville) and Kevin Kiley (R–Rocklin), respectively.

[33] The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense.

Glenn Ride runs buses from Willows to Hamilton City, and on into Chico (Butte County).

In 1884 the West Side and Mendocino Railroad constructed a line east from Willows to Fruto.

The population ranking of the following table is based on the 2010 census of Glenn County.