Roodhouse is a city in Greene County, Illinois, United States. The population was 1,578 at the 2020 census.

Roodhouse is located in northern Greene County at 39°28′55″N 90°22′18″W / 39.48194°N 90.37167°W / 39.48194; -90.37167 (39.482004, -90.371780). U.S. Route 67 passes through the center of the city, leading north 22 miles (35 km) to Jacksonville and south 13 miles (21 km) to Carrollton, the Greene County seat.

According to the 2021 census gazetteer files, Roodhouse has a total area of 1.13 square miles (2.93 km), all land.

Roodhouse was founded in the 1850s by John Roodhouse. The community was originally known as "The Crossroads" for its position on two major highways, though it was later renamed for its founder. In 1860, John Rawlins convinced the Chicago and Alton Railway to open a station in the community by promising to secure local funds for the depot and warehouse. The railway built its Louisiana branch from Roodhouse in 1871, and the city became a major junction point, boosting its population and economy. Roodhouse was legally incorporated as a city in 1880. Passenger railroad service to Roodhouse ended in the 1950s, causing a local economic downturn which persisted over the following decades.

The Hotel Roodhouse, the city's only surviving hotel from the railroad era, is listed on the National Register of Historic Places.

Historical population

Census	Pop.	Note	%±
1890	2,360		—
1900	2,351		−0.4%
1910	2,171		−7.7%
1920	2,928		34.9%
1930	2,621		−10.5%
1940	2,557		−2.4%
1950	2,368		−7.4%
1960	2,352		−0.7%
1970	2,357		0.2%
1980	2,364		0.3%
1990	2,139		−9.5%
2000	2,214		3.5%
2010	1,814		−18.1%
2020	1,578		−13.0%
U.S. Decennial Census

As of the 2020 census there were 1,578 people, 712 households, and 487 families residing in the city. The population density was 1,400.18 inhabitants per square mile (540.61/km). There were 792 housing units at an average density of 702.75 per square mile (271.33/km). The racial makeup of the city was 94.23% White, 0.06% African American, 0.00% Native American, 0.13% Asian, 0.00% Pacific Islander, 0.38% from other races, and 5.20% from two or more races. Hispanic or Latino of any race were 1.33% of the population.

There were 712 households, out of which 24.9% had children under the age of 18 living with them, 48.31% were married couples living together, 12.64% had a female householder with no husband present, and 31.60% were non-families. 29.35% of all households were made up of individuals, and 10.96% had someone living alone who was 65 years of age or older. The average household size was 2.81 and the average family size was 2.33.

The city's age distribution consisted of 22.7% under the age of 18, 6.2% from 18 to 24, 21.8% from 25 to 44, 28.8% from 45 to 64, and 20.4% who were 65 years of age or older. The median age was 42.6 years. For every 100 females, there were 104.4 males. For every 100 females age 18 and over, there were 99.1 males.

The median income for a household in the city was $38,977, and the median income for a family was $51,118. Males had a median income of $30,069 versus $23,958 for females. The per capita income for the city was $20,551. About 17.7% of families and 26.4% of the population were below the poverty line, including 36.2% of those under age 18 and 8.6% of those age 65 or over.