| Official Name: | Lake Township |
| Settlement Type: | Township |
| Image Map1: | Map of Illinois highlighting Clinton County.svg |
| Mapsize1: | 150px |
| Map Caption1: | Clinton County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Clinton |
| Area Total Sq Mi: | 29.93 |
| Area Land Sq Mi: | 29.8 |
| Area Water Sq Mi: | 0.13 |
| Area Water Percent: | 0.43 |
| Population As Of: | 2020 |
| Population Total: | 812 |
| Population Density Sq Mi: | auto |
| Elevation M: | 129 |
| Elevation Ft: | 423 |
| Coordinates: | 38.5369°N -89.3239°W |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Postal Code Type: | ZIP codes |
| Postal Code: | 62231, 62250, 62801 |
| Blank Name: | FIPS code |
| Blank Info: | 17-027-40871 |
| Unit Pref: | Imperial |
Lake Township is one of fifteen townships in Clinton County, Illinois, USA. As of the 2020 census, its population was 812 and it contained 373 housing units.[1] Lake Township was formed from part of Crooked Creek (Brookside) Township.
According to the 2010 census, the township has a total area of, of which (or 99.57%) is land and (or 0.43%) is water.[2]
(This list is based on USGS data and may include former settlements.)
The township contains these five cemeteries: Knolhoff (also known as Rose), Posey, Trinity Lutheran, Wadsworth, and Watts.[3]
As of the 2020 census there were 812 people, 342 households, and 269 families residing in the township. The population density was 27.14PD/sqmi. There were 373 housing units at an average density of 12.47/sqmi. The racial makeup of the township was 93.35% White, 0.49% African American, 0.49% Native American, 0.62% Asian, 0.00% Pacific Islander, 1.35% from other races, and 3.69% from two or more races. Hispanic or Latino of any race were 1.85% of the population.
There were 342 households, out of which 31.60% had children under the age of 18 living with them, 72.51% were married couples living together, 0.58% had a female householder with no spouse present, and 21.35% were non-families. 21.30% of all households were made up of individuals, and 10.20% had someone living alone who was 65 years of age or older. The average household size was 2.80 and the average family size was 3.27.
The township's age distribution consisted of 27.2% under the age of 18, 7.7% from 18 to 24, 25.6% from 25 to 44, 29.7% from 45 to 64, and 9.8% who were 65 years of age or older. The median age was 35.3 years. For every 100 females, there were 129.5 males. For every 100 females age 18 and over, there were 133.9 males.
The median income for a household in the township was $64,306, and the median income for a family was $86,528. Males had a median income of $45,357 versus $28,125 for females. The per capita income for the township was $27,316. No families and 1.7% of the population were below the poverty line, including none of those under age 18 and 4.3% of those age 65 or over.