| Official Name: | Cain Township |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Indiana |
| Subdivision Type2: | County |
| Subdivision Name2: | Fountain |
| Government Type: | Indiana township |
| Area Total Sq Mi: | 39.96 |
| Area Land Sq Mi: | 39.93 |
| Area Water Sq Mi: | 0.03 |
| Population As Of: | 2020 |
| Population Total: | 1112 |
| Population Density Sq Mi: | auto |
| Elevation Footnotes: | [1] |
| Elevation M: | 222 |
| Elevation Ft: | 728 |
| Coordinates: | 40.0831°N -87.1517°W |
| Blank Name: | FIPS code |
| Blank Info: | 18-09748 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 453152 |
Cain Township is one of eleven townships in Fountain County, Indiana. As of the 2020 census, its population was 1,112 and it contained 478 housing units.[2]
Cain Township was one of the first townships to be established in the county; it was established on July 24, 1826.[3] At that time, much of the land was forested, but 100 years later most of the land was used for agriculture. There were also several grain and lumber mills along Coal Creek, but these also were gone by the early 20th century. The town of Hillsboro was laid out in the 1830s and still exists; the town of Rynear was established in the far northwest corner of the township, but was gone by the early 1900s. The township's population was 1,763 in 1880, 1,537 in 1900, and 1,403 in 1910.[4]
According to the 2010 census, the township has a total area of, of which (or 99.92%) is land and (or 0.08%) is water.[5] There is a single settlement in the township: the town of Hillsboro, which has a population of about 500 (about half the township's total population). This lies at the intersection of the east–west U.S. Route 136[6] and the north–south Indiana State Road 341,[7] in the northern part of the township. Interstate 74 passes from east to west less than north of Hillsboro.[8] Indiana State Road 32 runs along a portion of the southern border of the township.[9]
The township contains three cemeteries. Rose Hill to the north and Spring Hill lie to the south of Hillsboro, while Scotts Prairie is in the far southwest corner of the township.