| Official Name: | Forty Mile Colony, Montana |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Montana#USA |
| Pushpin Label: | Forty Mile Colony |
| Pushpin Label Position: | top |
| Coordinates: | 45.2822°N -107.3561°W |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Montana |
| Subdivision Type2: | County |
| Subdivision Name2: | Big Horn |
| Area Footnotes: | [1] |
| Area Total Sq Mi: | 0.19 |
| Area Land Sq Mi: | 0.19 |
| Area Water Sq Mi: | 0.00 |
| Area Total Km2: | 0.50 |
| Area Land Km2: | 0.50 |
| Area Water Km2: | 0.00 |
| Population As Of: | 2020 |
| Population Density Km2: | 56.54 |
| Timezone: | Mountain (MST) |
| Utc Offset: | -7 |
| Timezone Dst: | MDT |
| Utc Offset Dst: | -6 |
| Elevation Ft: | 3438 |
| Postal Code Type: | ZIP Code |
| Postal Code: | 59050 (Lodge Grass) |
| Area Code: | 406 |
| Blank Name: | FIPS code |
| Blank Info: | 30-28725 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2806613 |
| Population Total: | 28 |
| Unit Pref: | Imperial |
| Population Density Sq Mi: | 146.60 |
Forty Mile Colony is a Hutterite colony[2] and census-designated place (CDP) in Big Horn County, Montana, United States, within the Crow Indian Reservation. It is in the valley of the Little Bighorn River, 3miles south of the town of Lodge Grass.
The location was first listed as a CDP prior to the 2020 census.