| Official Name: | Kirby |
| Settlement Type: | unincorporated community |
| Pushpin Map: | Montana#USA |
| Pushpin Map Caption: | Location in Montana |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Montana |
| Subdivision Type2: | County |
| Subdivision Name2: | Big Horn |
| Population As Of: | 2010 |
| Population Footnotes: | [1] |
| Population Total: | N/A |
| Population Density Sq Mi: | auto |
| Timezone: | Mountain (MST) |
| Utc Offset: | -7 |
| Timezone Dst: | MDT |
| Utc Offset Dst: | -6 |
| Elevation Ft: | 3878 |
| Coordinates: | 45.3325°N -106.9817°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 59042 |
| Area Code: | 406 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 777090 |
Kirby was an unincorporated community in Big Horn County, Montana, United States. The community location is at an elevation of 3878feet. The site is on the west bank of Rosebud Creek.[2] Rosebud Battlefield State Park lies approximately twelve miles south of the community, just west of Rosebud Creek.[3]
The town site of Kirby was at Montana Highway 314 and Cache Creek Road. It was directly east of the Crow Indian Reservation and south of the Northern Cheyenne Indian Reservation in the Rosebud Creek valley. A post office was operational from 1895 until 1970 with the ZIP Code of 59042.
Kirby is a ghost town with no more than a couple remaining buildings, including the former post office.