Oblong also boasts the largest nighttime marching band parade competition in the state of Illinois. The annual parade caps off the Oblong "Fall Follies" fall festival and event attended each year by hundreds of vendors and tens of thousands of spectators.
Oblong was originally a crossroads, notable only for its general store, owned by Henry Peck. The store featured a prominent sign, "Hen. Peck" and people of the area referred to the crossroads as "Henpeck." When the village decided to incorporate, it was decided that Henpeck would be a terrible name for their fair village. While surveying the area in conjunction with the incorporation, a rectangular prairie was identified on the outskirts of the community - and thus, Oblong was born.
Another claim to fame is that of a prominent headline in the Chicago Tribune - "Oblong Man Marries Normal Woman" - referring to the matrimony of a man from Oblong, Illinois and woman from Normal, Illinois.
According to the United States Census Bureau, the village has a total area of 1.0 square miles (2.5 km²), of which, 0.9 square miles (2.5 km²) of it is land and 1.04% is water.
There were 681 households out of which 27.6% had children under the age of 18 living with them, 48.9% were married couples living together, 12.3% had a female householder with no husband present, and 35.4% were non-families. 32.3% of all households were made up of individuals and 18.5% had someone living alone who was 65 years of age or older. The average household size was 2.25 and the average family size was 2.81.
In the village the population was spread out with 22.8% under the age of 18, 7.7% from 18 to 24, 24.9% from 25 to 44, 20.8% from 45 to 64, and 23.9% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 81.2 males. For every 100 females age 18 and over, there were 80.5 males.
The median income for a household in the village was $27,409, and the median income for a family was $36,532. Males had a median income of $27,135 versus $20,560 for females. The per capita income for the village was $14,926. About 7.0% of families and 9.9% of the population were below the poverty line, including 15.0% of those under age 18 and 5.6% of those age 65 or over.