Genoa is a city in the north-east corner of DeKalb County, Illinois, United States. It is located on the historic Galena-Chicago stagecoach route. At the 2010 census the city had a population of 5,193, up from 4,169 in 2000.
According to the 2010 census, Genoa has a total area of 2.655 square miles (6.88 km), of which 2.6 square miles (6.73 km) (or 97.93%) is land and 0.055 square miles (0.14 km) (or 2.07%) is water.
As of the census of 2000, there were 4,169 people, 1,555 households, and 1,119 families residing in the city. The population density was 2,178.8 people per square mile (842.8/km²). There were 1,597 housing units at an average density of 834.6 per square mile (322.8/km²). The racial makeup of the city was 95.27% White, 0.14% African American, 0.19% Native American, 0.29% Asian, 0.02% Pacific Islander, 3.14% from other races, and 0.94% from two or more races. Hispanic or Latino of any race were 10.65% of the population.
There were 1,555 households out of which 41.0% had children under the age of 18 living with them, 57.6% were married couples living together, 10.5% had a female householder with no husband present, and 28.0% were non-families. 24.3% of all households were made up of individuals and 9.7% had someone living alone who was 65 years of age or older. The average household size was 2.68 and the average family size was 3.21.
In the city the population was spread out with 30.6% under the age of 18, 8.2% from 18 to 24, 36.0% from 25 to 44, 16.1% from 45 to 64, and 9.1% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 97.5 males. For every 100 females age 18 and over, there were 95.2 males.
The median income for a household in the city was $48,125, and the median income for a family was $53,523. Males had a median income of $42,054 versus $28,060 for females. The per capita income for the city was $19,239. About 2.1% of families and 3.3% of the population were below the poverty line, including 3.9% of those under age 18 and 8.6% of those age 65 or over.