Osago township
- County:
- Nelson County
- County Seat:
- No
- Area (mi²):
- 35.398
- State:
- North Dakota
Osago township is located in Nelson County, North Dakota. Osago township has a 2025 population of 40. Osago township is currently declining at a rate of 0% annually and its population has decreased by 0% since the most recent census, which recorded a population of 40 in 2020.
The median age in Osago township is 14.5 years: 17.3 years for males, and 0 years for females.