| Unit Pref: | Imperial |
| Settlement Type: | Township |
| Official Name: | Marion Township |
| Image Map1: | Map of Illinois highlighting Lee County.svg |
| Mapsize1: | 150px |
| Map Caption1: | Lee County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Lee |
| Leader Title: | Supervisor |
| Leader Name: | S. Charles Dunphy |
| Established Title: | Established |
| Established Date: | September 1854 |
| Area Total Sq Mi: | 35.64 |
| Area Land Sq Mi: | 35.63 |
| Area Water Sq Mi: | 0.02 |
| Area Water Percent: | 0.06 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 6.5 |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 219 |
| Blank Name: | FIPS code |
| Blank Info: | 17-103-46890 |
Marion Township is located in Lee County, Illinois. As of the 2010 census, its population was 232 and it contained 114 housing units.[2]
Marion Township was formed from Hamilton and Amboy townships in September 1854. Three years later, on March 3, 1857, the western half of the township became Harmon Township allowing Marion Township to take its present form.[3]
According to the 2010 census, the township has a total area of, of which (or 99.97%) is land and (or 0.06%) is water.[2]