| Unit Pref: | Imperial |
| Settlement Type: | Township |
| Official Name: | Smithton Township |
| Image Map1: | Map of Illinois highlighting St. Clair County.svg |
| Mapsize1: | 150px |
| Map Caption1: | St. Clair County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Name: |  United States |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | St. Clair |
| Leader Title: | Supervisor |
| Established Title: | Established |
| Established Date: | November 6, 1883 |
| Area Total Sq Mi: | 32.91 |
| Area Land Sq Mi: | 32.28 |
| Area Water Sq Mi: | 0.63 |
| Area Water Percent: | 1.91 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 132.4 |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 4225 |
| Blank Name: | FIPS code |
| Blank Info: | 17-163-70265 |
Smithton Township (Township 1 South, Range 8 West) is located in St. Clair County, Illinois. As of the 2010 census, its population was 4,275 and it contained 1,684 housing units.[2]
According to the 2010 census, the township has a total area of, of which (or 98.09%) is land and (or 1.91%) is water.[2]
The current Members of the Smithton Township Board are Supervisor William F. Weber; Trustees Donald Barkau, Mark Rodriguez, Neil Espenschied, Quentin Grommet; Highway Commissioner Paul Reinneck; Clerk Troy L. Herring.
All seven Smithton Township Officials are serving a four-year term that ends in May, 2025.