Mackay
- County:
- Custer County
- County Seat:
- No
- Area (mi²):
- 0.866
- State:
- Idaho
Mackay is a city located in Custer County, Idaho. Mackay has a 2026 population of 480. Mackay is currently growing at a rate of 0.21% annually and its population has increased by 8.6% since the most recent census, which recorded a population of 442 in 2020.