Ogle County is a county in the northern part of the U.S. state of Illinois. According to the 2020 United States Census, it had a population of 51,788. Its county seat is Oregon, and its largest city is Rochelle. Ogle County comprises Rochelle, IL Micropolitan Statistical Area, which is also included in the Rockford-Freeport-Rochelle, IL Combined Statistical Area.

Ogle County was formed in 1836 out of Jo Daviess and LaSalle counties, and named in honor of Captain Joseph Ogle, a veteran of the Revolutionary War who settled in Illinois in 1785. Ogle County government was organized in 1837; before that time it remained assigned to Jo Daviess County for legislative, taxation, and judicial matters. In 1839, part of Ogle County was partitioned off to form Lee County.

Ogle County was a New England settlement. The founders of Oregon and Rochelle arrived from New England; they were "Yankees", descendants of English Puritans who had settled New England in the 1600s. They were part of a wave of farmers who migrated into the Northwest Territory in the early 1800s, their trek eased by completion of the Erie Canal in 1825. They found virgin forest and wild prairie, and quickly laid out farms, constructed roads, erected government buildings and established post routes. They brought a passion for education and strong abolitionism. They were members of the Congregationalist or Episcopalian Church. Culturally Ogle County, like much of northern Illinois would maintain values similar to those of New England.

• 
  Ogle County between 1836 and 1839
• 
  Ogle County after 1839, when Lee County was formed

According to the US Census Bureau, the county has a total area of 763 square miles (1,980 km), of which 759 square miles (1,970 km) is land and 4.4 square miles (11 km) (0.6%) is water.

• Winnebago County - north
• Boone County - northeast
• Stephenson County - northwest
• DeKalb County - east
• Carroll County - west
• Lee County - south
• Whiteside County - southwest

Oregon, Illinois
Climate chart (explanation)
J F M A M J J A S O N D     1.6     26 10     1.4     32 15     2.6     44 27     3.6     58 37     4.3     70 48     4.9     79 58     3.5     82 62     4.5     80 60     3.3     73 51     2.7     62 39     2.8     45 28     2.1     31 17 █ Average max. and min. temperatures in °F █ Precipitation totals in inches Source: The Weather Channel
Metric conversion J F M A M J J A S O N D     41     −3 −12     36     0 −9     65     7 −3     92     14 3     110     21 9     124     26 14     88     28 17     114     27 16     84     23 11     69     17 4     72     7 −2     54     −1 −8 █ Average max. and min. temperatures in °C █ Precipitation totals in mm

In recent years, average temperatures in Oregon have ranged from a low of 10 °F (−12 °C) in January to a high of 82 °F (28 °C) in July, although a record low of −27 °F (−33 °C) was recorded in January 1999 and a record high of 110 °F (43 °C) was recorded in July 1936. Average monthly precipitation ranged from 1.43 inches (36 mm) in February to 4.88 inches (124 mm) in June.

Historical population

Census	Pop.	Note	%±
1840	3,479		—
1850	10,020		188.0%
1860	22,888		128.4%
1870	27,492		20.1%
1880	29,937		8.9%
1890	28,710		−4.1%
1900	29,129		1.5%
1910	27,864		−4.3%
1920	26,830		−3.7%
1930	28,118		4.8%
1940	29,869		6.2%
1950	33,429		11.9%
1960	38,106		14.0%
1970	42,867		12.5%
1980	46,338		8.1%
1990	45,957		−0.8%
2000	51,032		11.0%
2010	53,497		4.8%
2020	51,788		−3.2%
2023 (est.)	51,265		−1.0%
US Decennial Census 1790-1960 1900-1990 1990-2000 2010

Ogle County, Illinois – Racial and ethnic composition
Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.

Race / Ethnicity (NH = Non-Hispanic)	Pop 2000	Pop 2010	Pop 2020	% 2000	% 2010	% 2020
White alone (NH)	47,057	47,425	43,120	92.21%	88.65%	83.26%
Black or African American alone (NH)	204	468	543	0.40%	0.87%	1.05%
Native American or Alaska Native alone (NH)	89	91	72	0.17%	0.17%	0.14%
Asian alone (NH)	209	241	259	0.41%	0.45%	0.50%
Pacific Islander alone (NH)	19	5	0	0.04%	0.01%	0.00%
Other race alone (NH)	19	19	104	0.04%	0.04%	0.20%
Mixed race or Multiracial (NH)	369	507	1,893	0.72%	0.95%	3.66%
Hispanic or Latino (any race)	3,066	4,741	5,797	6.01%	8.86%	11.19%
Total	51,032	53,497	51,788	100.00%	100.00%	100.00%

As of the 2010 United States census, there were 53,497 people, 20,856 households, and 14,711 families residing in the county. The population density was 70.5 inhabitants per square mile (27.2/km). There were 22,561 housing units at an average density of 29.7 per square mile (11.5/km). The racial makeup of the county was 93.2% white, 0.9% black or African American, 0.5% Asian, 0.2% American Indian, 3.8% from other races, and 1.4% from two or more races. Those of Hispanic or Latino origin made up 8.9% of the population. In terms of ancestry, 38.0% were German, 15.3% were Irish, 10.2% were English, 6.4% were American, 5.3% were Swedish, and 5.3% were Norwegian.

Of the 20,856 households, 33.1% had children under the age of 18 living with them, 56.1% were married couples living together, 9.7% had a female householder with no husband present, 29.5% were non-families, and 24.5% of all households were made up of individuals. The average household size was 2.54 and the average family size was 3.01. The median age was 40.7 years.

The median income for a household in the county was $55,733 and the median income for a family was $64,927. Males had a median income of $49,996 versus $32,082 for females. The per capita income for the county was $24,959. About 6.6% of families and 8.9% of the population were below the poverty line, including 12.4% of those under age 18 and 5.9% of those age 65 or over.

By 2000, 65% of the county labor force was employed as white-collar workers with an increase of 20 points in comparison with 1990 statistics. Manufacturing remains the leading employment sector absorbing more than 21.7% of the labor force though there was a decrease from 30,4% in 1995. However it is expected that services would replace manufacturing starting 2015 as the leading activity.

Agriculture remains important in Ogle county, mainly corn and soybeans. In 2003, the Illinois Department of Agriculture ranked Ogle County 17th in the State for crop cash receipts, and 14th in the state for livestock cash receipts. As for livestock production, hogs and pigs are still leading even though productions decreased from 57,000 units in 1998 to 48,900 in 2002.

The county also got some investment packages such as a $180 million truck-to-train cargo hub in 2006. In August 2006, it was announced that a new ethanol production facility would receive a package of $5.5 million Opportunity Returns grant from the State.

United States presidential election results for Ogle County, Illinois

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	16,450	63.76%	8,883	34.43%	466	1.81%
2020	16,248	61.69%	9,428	35.79%	664	2.52%
2016	14,352	59.32%	8,050	33.27%	1,791	7.40%
2012	13,422	57.44%	9,514	40.72%	431	1.84%
2008	13,144	52.72%	11,253	45.13%	537	2.15%
2004	14,918	61.92%	9,018	37.43%	155	0.64%
2000	12,325	59.83%	7,673	37.25%	603	2.93%
1996	9,558	52.13%	6,765	36.90%	2,012	10.97%
1992	9,008	44.80%	6,512	32.38%	4,589	22.82%
1988	11,644	66.94%	5,641	32.43%	109	0.63%
1984	13,503	73.40%	4,803	26.11%	90	0.49%
1980	12,533	66.41%	4,067	21.55%	2,271	12.03%
1976	11,073	62.22%	6,463	36.32%	261	1.47%
1972	13,512	73.88%	4,743	25.93%	35	0.19%
1968	12,168	68.98%	4,399	24.94%	1,074	6.09%
1964	10,430	60.13%	6,917	39.87%	0	0.00%
1960	13,226	73.38%	4,792	26.59%	7	0.04%
1956	13,194	78.21%	3,660	21.70%	16	0.09%
1952	13,351	77.79%	3,796	22.12%	16	0.09%
1948	9,519	71.15%	3,796	28.37%	63	0.47%
1944	10,680	72.59%	3,951	26.86%	81	0.55%
1940	11,838	70.71%	4,833	28.87%	71	0.42%
1936	9,576	61.60%	5,776	37.15%	194	1.25%
1932	8,224	59.11%	5,416	38.93%	272	1.96%
1928	9,808	78.18%	2,691	21.45%	47	0.37%
1924	8,449	71.61%	1,591	13.48%	1,759	14.91%
1920	9,322	82.99%	1,720	15.31%	191	1.70%
1916	8,639	70.30%	3,207	26.10%	442	3.60%
1912	2,014	29.86%	1,750	25.95%	2,981	44.20%
1908	4,848	69.24%	1,761	25.15%	393	5.61%
1904	5,109	75.14%	1,209	17.78%	481	7.07%
1900	5,255	68.97%	2,171	28.49%	193	2.53%
1896	5,210	69.20%	2,142	28.45%	177	2.35%
1892	3,939	60.61%	2,244	34.53%	316	4.86%

Along with its neighbor Lee County, Ogle County is one of the most consistently Republican counties in the nation when it comes to presidential elections. Except for the 1912 election when the GOP was divided between Progressive nominee Theodore Roosevelt and incumbent president William Howard Taft, Ogle County has voted Republican in every Presidential election since the Republican Party first participated in 1856. No Democratic candidate has ever won the county, which favored the Whig Party before the Republican Party was formed.

Historically, Republicans have easily carried the county in statewide and national Democratic landslides. Franklin D. Roosevelt never garnered more than 39 percent of the county's vote in any of his four runs for president, and Barry Goldwater won over 60 percent here in 1964–almost identical to Lyndon Johnson's winning margin statewide. Illinois' own Barack Obama is the only Democrat to ever win at least 40 percent of the county's vote.

The county is part of Illinois's 16th congressional district. represented by Republican Darin LaHood.

• List of intercity bus stops in Illinois

The following public-use airports are located in the county:

• Ogle County Airport (C55) - Mount Morris, Illinois
• Rochelle Municipal Airport (RPJ) - Rochelle, Illinois

The Union Pacific line to Omaha (Chicago & North Western), BNSF line to Minneapolis (Burlington Route, later Burlington Northern), Canadian Pacific Kansas City line to Sabula (Milwaukee Road) all run through Ogle County.

• Beach Cemetery Prairie Nature Preserve
• Douglas E. Wade Prairie Nature Preserve
• Jarrett Prairie Nature Preserve
• Nachusa Grasslands

• Byron
• Oregon
• Polo
• Rochelle

• Grand Detour
• Lost Nation

• List of settlements in Ogle County, Illinois
• List of townships in Ogle County, Illinois
• List of cemeteries in Ogle County, Illinois
• National Register of Historic Places listings in Ogle County, Illinois

• Kauffman, Horace G.; Kauffman, Rebecca H., eds. (1909). Historical Encyclopedia of Illinois and History of Ogle County. Vol. 2. Chicago: Munsell Publishing Co. Retrieved November 23, 2010.
• The History of Ogle County, Illinois. Chicago: H. F. Kett & Co. 1878. Retrieved November 23, 2010.

• Official website
• Ogle County History
• Ogle County History

42°02′N 89°19′W / 42.04°N 89.32°W / 42.04; -89.32