Donaldsonville
- County:
- Ascension Parish
- County Seat:
- No
- Area (mi²):
- 3.778
- State:
- Louisiana
Donaldsonville is a city located in Ascension Parish, Louisiana. Donaldsonville has a 2026 population of 6,945. Donaldsonville is currently growing at a rate of 1.06% annually and its population has increased by 3.52% since the most recent census, which recorded a population of 6,709 in 2020.