Alger is a village in Hardin County, Ohio, United States. The population was 860 at the 2010 census.
Alger was first called Jagger, and under the latter name was laid out in 1882 by Elias Jagger, and named for him. The present name is for Russell A. Alger, 20th Governor of Michigan. The village was incorporated in 1896.
Alger is located on State Route 235 about 4 miles (6.4 km) south of Ada.
According to the United States Census Bureau, the village has a total area of 0.28 square miles (0.73 km2), all of it land.
As of the census of 2010, there were 860 people, 347 households, and 232 families living in the village. The population density was 3,071.4 inhabitants per square mile (1,185.9/km2). There were 413 housing units at an average density of 1,475.0 per square mile (569.5/km2). The racial makeup of the village was 97.2% White, 0.2% African American, 0.5% Native American, 0.1% Asian, 0.1% from other races, and 1.9% from two or more races. Hispanic or Latino of any race were 1.2% of the population.
There were 347 households, of which 34.3% had children under the age of 18 living with them, 46.4% were married couples living together, 17.3% had a female householder with no husband present, 3.2% had a male householder with no wife present, and 33.1% were non-families.