
Niagara County
- State:
- New York
Niagara County's estimated 2025 population is 207,437 with a growth rate of -0.48% in the past year according to the most recent United States census data. Niagara County is the 18th largest county in New York. The 2010 population was 216,474 and has seen a growth of -4.17% since that time.