[2] The county was formed in 1846[3] and was named for Robert Lucas, a Governor of the Territory.

[12] As of the census[13] of 2000, there were 9,422 people, 3,811 households, and 2,560 families residing in the county.

The racial makeup of the county was 98.44% White, 0.13% Black or African American, 0.11% Native American, 0.30% Asian, 0.01% Pacific Islander, 0.37% from other races, and 0.65% from two or more races.

28.70% of all households were made up of individuals, and 14.60% had someone living alone who was 65 years of age or older.

The population ranking of the following table is based on the 2020 census of Lucas County.