Prior to its incorporation in 1834, the first settlements in the village were to the east of the present village site. The village was an early center for the manufacture of patent medicines by companies such as S. C. Wells & Co. and household chemicals. Products produced in Le Roy included Mustarine, a patent mustard-plaster compound, and Rough On Rats, a rodent poison. Earliest businesses in the village are the Bank of LeRoy and the Gazette-News newspaper. Le Roy is the birthplace of Jell-O. Le Roy holds the Oatka Festival every summer, the tradition originating in 1989. This festival includes celebration of the rich culture and history of the local area with vendors and several local businesses and restaurants participating each year. The First Presbyterian Church of Le Roy, Keeney House, Machpelah Cemetery, Le Roy House and Union Free School, Augustus S. Tyron House, U.S. Post Office, and Marion Steam Shovel are listed on the National Register of Historic Places.
As of the census of 2000, there were 4,462 people, 1,845 households, and 1,114 families residing in the village. The population density was 1,654.8 people per square mile. There were 1,980 housing units at an average density of 734.3 per square mile. The racial makeup of the village was 94.73% White, 2.47% Black or African American, 0.38% Native American, 0.56% Asian, 0.02% Pacific Islander, 0.22% from other races, and 1.61% from two or more races. Hispanic or Latino of any race were 0.92% of the population. There were 1,845 households out of which 29.7% had children under the age of 18 living with them, 44.1% were married couples living together, 11.5% had a female householder with no husband present, and 39.6% were non-families. 33.3% of all households were made up of individuals and 14.5% had someone living alone who was 65 years of age or older. The average household size was 2.35 and the average family size was 3.04. In the village, the population was spread out with 25.0% under the age of 18, 7.3% from 18 to 24, 28.6% from 25 to 44, 21.7% from 45 to 64, and 17.4% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 87.4 males. For every 100 females age 18 and over, there were 82.0 males. The median income for a household in the village was $33,168, and the median income for a family was $43,594. Males had a median income of $36,740 versus $21,306 for females. The per capita income for the village was $18,565. About 6.1% of families and 7.3% of the population were below the poverty line, including 7.1% of those under age 18 and 10.1% of those age 65 or over.
