Jo Daviess County, Illinois

County border changes

• 1830 – The northern border of Illinois and Wisconsin was formally established. Until that time, several Wisconsin towns actually were under the jurisdiction of Jo Daviess County.^[8]
• 1831 – Rock Island County was formed from a part of the county, along with a new northern extension of Henry County and Putnam County.
• 1836 – Whiteside, Ogle, and Winnebago counties were formed from the southern and eastern sections of the county.
• 1837 – Stephenson County was formed from the eastern section of the county.
• 1839 – Carroll County was formed from the southern section of the county.

• 
  Jo Daviess County at the time of its creation to 1831 (Wisconsin border adjustment not shown)
• 
  Jo Daviess between 1831 and 1836
• 
  Jo Daviess between 1836 and 1837. Whiteside and Ogle counties remained temporarily attached to Jo Daviess until county governments could be organized.^[9]
• 
  Jo Daviess between 1837 and 1839
• 
  Jo Daviess reduced to its current size in 1839 by the creation of Carroll County and the organization of a government in Whiteside County

Climate and weather

In recent years, average temperatures in the county seat of Galena have ranged from a low of 9 °F (−13 °C) in January to a high of 84 °F (29 °C) in July, although a record low of −35 °F (−37 °C) was recorded in February 1996 and a record high of 103 °F (39 °C) was recorded in August 1988. Average monthly precipitation ranged from 1.14 inches (29 mm) in January to 4.58 inches (116 mm) in June.^[11]

Major highways

In Illinois, US 20 is designated the General Ulysses S. Grant Highway (often abbreviated the U.S. Grant Memorial Highway) and is the longest route in the United States.^[12] In eastern Jo Daviess County US 20 is one of the few areas that remain two-lane across the entire stretch of US 20. The road between Dubuque and Stockton was once known as the most dangerous stretch of road because of the hills and curves flanked by cliffs and valleys. Travelers were greeted with signs reminding them to drive carefully as they entered this stretch of road.

• U.S. Route 20
• Illinois Route 35
• Illinois Route 78
• Illinois Route 84

Adjacent counties

National protected area

• Upper Mississippi River National Wildlife and Fish Refuge (part)

State protected area

• Apple River Canyon State Park

Locally protected area

Several areas are protected by the charitable organization Jo Daviess Conservation Foundation:^[13]

• Buehler Preserve
• Casper Bluff Land & Water Reserve
• Horseshoe Mound
• Schurmeier Teaching Forest
• Valley of Eden Bird Sanctuary
• Wapello Land & Water Reserve

2020 census

As of the 2020 census, the county had a population of 22,035. The median age was 50.1 years. 19.2% of residents were under the age of 18 and 28.0% of residents were 65 years of age or older. For every 100 females there were 100.5 males, and for every 100 females age 18 and over there were 98.5 males age 18 and over.^[29][30]

The racial makeup of the county was 93.4% White, 0.5% Black or African American, 0.3% American Indian and Alaska Native, 0.4% Asian, <0.1% Native Hawaiian and Pacific Islander, 1.5% from some other race, and 3.8% from two or more races. Hispanic or Latino residents of any race comprised 3.9% of the population.^[30]

11.6% of residents lived in urban areas, while 88.4% lived in rural areas.^[31]

There were 9,827 households in the county, of which 22.9% had children under the age of 18 living in them. Of all households, 51.3% were married-couple households, 18.6% were households with a male householder and no spouse or partner present, and 23.5% were households with a female householder and no spouse or partner present. About 31.1% of all households were made up of individuals and 16.5% had someone living alone who was 65 years of age or older.^[29]

There were 13,408 housing units, of which 26.7% were vacant. Among occupied housing units, 79.1% were owner-occupied and 20.9% were renter-occupied. The homeowner vacancy rate was 2.6% and the rental vacancy rate was 12.5%.^[29]

2010 census

As of the 2010 United States census, there were 22,678 people, 9,753 households, and 6,514 families residing in the county.^[32] The population density was 37.7 inhabitants per square mile (14.6/km²). There were 13,574 housing units at an average density of 22.6 per square mile (8.7/km²).^[10] The racial makeup of the county was 97.2% White, 0.5% Black or African American, 0.3% Asian, 0.2% American Indian, 0.9% from other races, and 0.9% from two or more races. Those of Hispanic or Latino origin made up 2.7% of the population.^[32] In terms of ancestry, 49.4% were German, 19.7% were Irish, 11.1% were English, and 8.5% were American.^[33]

Of the 9,753 households, 25.3% had children under the age of 18 living with them, 55.9% were married couples living together, 7% had a female householder with no husband present, 33.2% were non-families, and 28.4% of all households were made up of individuals. The average household size was 2.31 and the average family size was 2.81. The median age was 47.1 years.^[32]

The median income for a household in the county was $50,279 and the median income for a family was $60,381. Males had a median income of $38,372 versus $29,412 for females. The per capita income for the county was $26,819. About 5.6% of families and 8.4% of the population were below the poverty line, including 11.5% of those under age 18 and 6.4% of those age 65 or over.^[34]

Cities

• East Dubuque 1505
• Galena (county seat) 3308
• Stockton 1728

Villages

Census-designated places

• Apple Canyon Lake
• The Galena Territory

Townships

Jo Daviess County is divided into twenty-three townships:

Unincorporated communities

Historic site

• Apple River Fort