New Castle
- County:
- Henry County
- County Seat:
- Yes
- Area (mi²):
- 7.324
- State:
- Indiana
New Castle is a city located in Henry County, Indiana. New Castle has a 2026 population of 17,382. It is also the county seat of Henry County. New Castle is currently growing at a rate of 0.14% annually but its population has decreased by -0.11% since the most recent census, which recorded a population of 17,401 in 2020.