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The Commemorative
Quarter for
California

The Commemorative Quarter for California





Welcome to Diamond Bar ...

The city of Diamond Bar is located in Los Angeles County<1>.

From the  Census Estimates for 2019, Diamond Bar has a population of 55,489 people<2> (see below for details).

Diamond Bar is 930 feet [283 m] above sea level.<3>.

Time Zone: Diamond Bar lies in the Pacific Time Zone (PST/PDT) and observes daylight saving time

Area Codes for Diamond Bar: 909 & 840<4>

The ZIP code for Diamond Bar: 91765<5>

Population Details ...

Taken from the 2019 Census Estimates, Diamond Bar had an population of 55,489 people. This is a decrease of 0.1% since the 2010 Census (or a decrease of 1.42% since the 2000 Census).

At the time of the 2010 Census, Diamond Bar had a population of 55,544 people. This makes Diamond Bar the county's 34th most populous community.

The population of Diamond Bar represents 0.15% of the population of California (which has 37,253,956 people), making it the state's 151st most populous community.

With a 2010 count of 55,544 people, the population of Diamond Bar decreased 1.32% from the 2000 Census (which had a count of 56,287 people).

More information can be found on the Census Page for Diamond Bar.

Websites for Diamond Bar ...

Official Website:   www.ci.diamond-bar.ca.us/

Chamber of Commerce:   www.diamondbarchamber.com/

Communities near Diamond Bar ...

We have created a list of 10 communities that are near Diamond Bar.

To Help With Your Genealogy Research ...

We have a couple of sections for those tracing their genealogy.

We created a list of cemeteries that are in the area around Diamond Bar. Our list includes the location of those cemeteries and we provide an overhead view. See our Cemetery List for Diamond Bar.

Using the information from an 1895 Atlas, we've created a list of communities that were in the area of Diamond Bar. Our list includes information such as whether the 1895 community had a post office or railroad service. See our List of 1890's Communities around Diamond Bar.

We also have a detailed list of newspapers that have been published in the area around Diamond Bar. See our Newspapers Page for Diamond Bar.

TripAdvisor Tourism Pages for Diamond Bar ...

Looking for more information about Diamond Bar? A wonderful source is the TripAdvisor website. We always start with the TripAdvisor Tourism page, where you can read an overview with links that will help you find lodging, restaurants and attractions.

In addition to the Tourism page for Diamond Bar, there are neighboring communities that also have Tourism pages. More information about those communities can be found on our TripAdvisor Page for Diamond Bar.

Adding Diamond Bar to Our Gazetteer ...

We originally found mention of Diamond Bar in both the FIPS-55 and the GNIS. For more information, see the FIPS and GNIS Codes sections on our Miscellaneous Page.

From our notes, the earliest published mention we've found for Diamond Bar was in the book titled SPV's Comprehensive Railroad Atlas of North America - California & Nevada.

For more details, see References and Mentions for Diamond Bar.

The official website for Diamond Bar: www.ci.diamond-bar.ca.us/

The official website for Los Angeles County: www.lacounty.info/

The official website for State of California: https://www.ca.gov/

Footnotes ...

<1>If you're interested in how the shape of California's counties, including Los Angeles, have changed over time, we recommend the Atlas of Historical County Boundaries.
<2>Population counts have been provided by the U.S. Census Bureau. For more detail, please visit our Census Page for Diamond Bar.
<3>The elevation is an estimate for the area around Diamond Bar - it will be higher in some places and lower in others.
<4>When there's a risk of an area code running out of phone numbers, an 'Overlay Area Code' is created that has the same geographic boundaries as the existing area code. In this case, the 909 code has been Overlayed with the 840 area code. New phone numbers in the Diamond Bar area will be assigned with one of these codes: 909 or 840. As a result, placing a call in the Diamond Bar area will require 10-digit dialing (where you enter both the area code and then the phone number).
<5>ZIP Codes have been created by the United States Postal Service (USPS) as a way of grouping addresses to make delivery more efficient. The boundaries of the ZIP Code can be changed, re-assigned, eliminated or overlapped with other ZIP Codes. So keep in mind that any given ZIP Code is only 'loosely' associated with a city (such as Diamond Bar). When looking for a ZIP Code, whether Diamond Bar or elsewhere, it's always best to check the website of the United States Postal Service (USPS).
<6>While we're fans and frequent users of TripAdvisor, you should know that we're also members of the TripAdvisor affiliate program.




 

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This page was last modified/updated: 28 Apr 2025