Population
51,884
Diamond BarCensus, July 2025
From 55,006 in July 2020 to 51,884 in July 2025.
The Census Bureau's estimate of everyone living here on July 1.
Diamond Bar by the numbers
Official figures for Diamond Bar. Each one shows its date, its source and the area it covers. A figure for a larger area says so.
People
Change in a year
-0.8%
Diamond BarCensus, 2024 to 2025
Change in the population estimate over one year, from July 1 to July 1, both from the same release.
Change over 5 years
-5.7%
Diamond BarCensus, 2020 to 2025
Change in the population estimate over five years, from July 1 to July 1, both from the same release.
Sources
- U.S. Census Bureau, Population Estimates, Vintage 2025 · Public domain
Figures are shown as each source publishes them. Survey figures carry a 90% margin of error. A figure for a larger area is labelled with that area.