Los Angeles County

Diamond Bar, CA Business Index

Diamond Bar is a city in Los Angeles County with an estimated 51,884 residents as of 2025, down 5.7% since 2020. Diamond Bar's business base is indexed below across 48 owner-operated industries.

Population (2025)
51,884
U.S. Census Bureau estimate
Change since 2020
-5.7%
2020–2025
Land area
14.9 sq mi
2023 Census Gazetteer
Density
3,487/sq mi
Residents per square mile

Population trend

Annual resident population estimates, U.S. Census Bureau Population Estimates Program.

YearPopulationYear over year
202055,006n/a
202153,847-2.11%
202253,036-1.51%
202352,539-0.94%
202452,288-0.48%
202551,884-0.77%

Diamond Bar holds 0.5% of Los Angeles County’s 9,694,934 residents.

Industries in Los Angeles County

Diamond Bar businesses compete in the Los Angeles County market. Establishment counts, employment and payroll below are reported at county level by the U.S. Census Bureau.

HVAC & PlumbingViewElectricalViewRoofingViewLandscapingViewPest ControlViewPool ServiceViewCommercial CleaningViewFlooringViewGlass & GlazingViewSeptic & WellViewAuto RepairViewAuto BodyViewCar WashViewTowingViewTruckingViewEquipment RentalViewDentalViewVeterinaryViewHome HealthViewPharmacyViewMedical PracticeViewOptometryViewAccountingViewInsurance AgencyViewIT & MSPViewStaffingViewEngineeringViewArchitectureViewLaw FirmViewSecurity ServicesViewPrintingViewSign ShopsViewMachine ShopsViewMetal FabricationViewPlasticsViewFood ManufacturingViewMillworkViewRestaurantsViewBakeriesViewLiquor StoresViewGyms & FitnessViewSalons & SpasViewLaundromatsViewDry CleaningViewFuneral HomesViewSelf StorageViewChildcareViewPet ServicesView

Nearby cities

Other indexed places in Los Angeles County and the surrounding area.

Los Angeles3,869,089Long Beach450,469Santa Clarita228,430Glendale187,160Lancaster170,084Palmdale161,845Pomona147,807Torrance138,391Pasadena135,804
Data last refreshed from source on 2026-09-08.

Sources

  1. U.S. Census Bureau, Population Estimates Program (Vintage 2025). Subcounty resident population estimates. Retrieved 2026-09-08.
  2. U.S. Census Bureau, 2023 Gazetteer Files. Land area and internal point coordinates. Retrieved 2026-09-08.
  3. U.S. Census Bureau, ANSI/FIPS Place-to-County Relationship File Retrieved 2026-09-08.