There were 551 households out of which 28.7% had children under the age of 18 living with them, 51.4% were married couples living together, 8.9% had a female householder with no husband present, and 35.8% were non-families. 33.2% of all households were made up of individuals and 18.9% had someone living alone who was 65 years of age or older. The average household size was 2.29 and the average family size was 2.86.
In the town the population was spread out with 25.6% under the age of 18, 7.0% from 18 to 24, 27.0% from 25 to 44, 21.1% from 45 to 64, and 19.3% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 82.8 males. For every 100 females age 18 and over, there were 81.4 males.
The median income for a household in the town was $34,474, and the median income for a family was $41,417. Males had a median income of $35,650 versus $17,292 for females. The per capita income for the city was $16,421. About 5.2% of families and 9.5% of the population were below the poverty line, including 11.6% of those under age 18 and 11.7% of those age 65 or over.
What is now called Assumption was once called Tacusah. Around 1840-50, a stagecoach road from Springfield to Terre Haute stopped at the "Halfway House", some four miles east of Assumption near the Potter farms. This house was occupied within the memory of many now living by the Heber Keirn family. In 1840 the need of a railroad became acute, as produce and supplies had to be hauled long distances by wagon. Stock was driven as far as St. Louis to market. Until the building of the railroad, the town had few settlers. A few adventurers had disposed of the deer and wolves and driven the Indians north- and west-ward. Life in the fifties and sixties was primitive. Winters were long, log cabins poorly heated. In December 1856, there came to Tacusah a remarkable man, Elisee E. Malhiot. With him came his brother Francis. He wished to found a Canadian colony of his friends and relatives-so, he induced 150 men, women and children from his early home to come to his settlement. He gave the name Assumption to his venture, in honor of his former Louisiana parish. Among the people from Canada were many mechanics and farmers. Soon, thirty or more houses were built. In 1858 Colonel Malhiot erected a large flour mill. He brought sugar from his Louisiana plantation and sold it at wholesale prices to his neighbors. Marcus L. Barrett from Massachusetts was another factor in the town's growth. He first conducted a boarding house for men working on the railroad. In 1902 the village was incorporated as a city.
Enrollment at the middle school is approximately 220 students.
Assumption is also home to Kemmerer Village, a private Presbyterian childcare agency, named for donor Philip Kemmerer who willed 400 acres to "the orphans and friendless poor of all denominations" in 1884. Originally known as Kemmerer Orphan Home, the facility opened in 1914. In 1930, the named was changed to Kemmerer Children's Home. Eventually the name became Kemmerer Village. Kemmerer Village website See also Kemmerer Village Campus Center