O’fallon and Shiloh are “sister communities”, similar in demographics that share a common high school district (District 203) and occupy a common township (O’fallon Township).  Separate demographic descriptions follow for both O’fallon and Shiloh.

O’fallon, Illinois Demographic Summary:

(The 2010 Census said 28,281 people lived in O'Fallon, a 20% change since 2000.)  As of a special census of 2005, there are 25,647 (up 3,737 from the census of 2000) people and 10,468 households. There is an average of 2 people per household, down from 2.4 in 2000. The significant increase in population can be attributed to two main factors: 1. the ever-expanding suburbs of metropolitan St. Louis, Missouri and 2. the influx of military personnel from nearby Scott Air Force Base.

The population density is 775.4/km² (2,007.6/mi²). There are 10,468 housing units at an average density of 305.3/km² (790.4/mi²). The racial makeup of the city is 82.67% White, 11.99% African American, 0.23% Native American, 2.47% Asian, 0.07% Pacific Islander, 0.79% from other races, and 1.77% from two or more races. 2.23% of the population are Hispanic or Latino of any race.

There are 10,468 households out of which 39.6% have children under the age of 18 living with them, 59.0% are married couples living together, 10.5% have a female householder with no husband present, and 27.6% are non-families. 23.2% of all households are made up of individuals and 7.2% have someone living alone who is 65 years of age or older. The average household size is 2.62 and the average family size is 3.13.

In the city the population is spread out with 28.3% under the age of 18, 8.0% from 18 to 24, 32.2% from 25 to 44, 22.7% from 45 to 64, and 8.9% who are 65 years of age or older. The median age is 35 years. For every 100 females there are 93.2 males. For every 100 females age 18 and over, there are 90.1 males.

The median income for a household in the city is $55,927, and the median income for a family is $66,262. Males have a median income of $46,303 versus $30,158 for females. The per capita income for the city is $24,821. 5.0% of the population and 4.1% of families are below the poverty line. Out of the total population, 5.0% of those under the age of 18 and 7.9% of those 65 and older are living below the poverty line.  (Source: Wikipedia)

For an in-depth demographic report, use this “City-Data” link: http://www.city-data.com/township/O-Fallon-St.-Clair-IL.html

Shiloh, Illinois Demographic Summary:

(In 2010, the population was listed as 12,651, an increase of 65% since 2000.)   In 2005, another census was done and the  population of Shiloh was then about 11,000.  In other respects, the following is from the census of 2000:

As of the censusGR2 of 2000, there were 7,643 people, 2,778 households, and 2,080 families residing in the village. The population density was 293.6/km² (760.2/mi²). There were 2,928 housing units at an average density of 112.5/km² (291.2/mi²). The racial makeup of the village was 82.14% White, 13.32% African American, 0.27% Native American, 1.79% Asian, 0.08% Pacific Islander, 0.75% from other races, and 1.65% from two or more races. Hispanic or Latino of any race were 2.62% of the population.

There were 2,778 households out of which 40.9% had children under the age of 18 living with them, 60.8% were married couples living together, 10.7% had a female householder with no husband present, and 25.1% were non-families. 20.2% of all households were made up of individuals and 5.1% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.05.

In the village the population was spread out with 27.7% under the age of 18, 10.7% from 18 to 24, 34.6% from 25 to 44, 20.4% from 45 to 64, and 6.7% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 102.0 males. For every 100 females age 18 and over, there were 98.0 males.

The median income for a household in the village was $57,692, and the median income for a family was $67,054. Males had a median income of $42,083 versus $30,843 for females. The per capita income for the village was $25,550. About 6.1% of families and 7.7% of the population were below the poverty line, including 11.1% of those under age 18 and 1.6% of those age 65 or over.   Source: Wikipedia.