Draft Supplemental Environmental Analysis for Town Center Specific Plan Now Available

The draft Supplemental Environmental Impact Report (SIR) for the proposed Diamond Bar Town Center Specific Plan is now available for public review and comment. Prepared under California Environmental Quality Act requirements, the Draft SIR evaluates the Specific Plan's potential environmental impacts and identifies ways to avoid, minimize, or offset those considered significant.

Environmental Impacts

In total, the draft SIR analyzed nine environmental issue areas: aesthetics, air quality, greenhouse gas emissions, hydrology and water quality, noise, public services, recreation, transportation, and utilities and service systems. Only air quality and transportation were identified as significant and unavoidable project impacts. The other seven areas were determined to have no impact to less-than-significant impact.

About the Project

The proposed Town Center Specific Plan involves the phased development of existing suburban-style retail shopping centers to create a pedestrian-oriented "Town Center" that will expand housing opportunities, retail, restaurants, and entertainment in Diamond Bar. The Specific Plan area consists of approximately 45 acres bounded by the 60 Freeway on the north, by a neighborhood of single-family homes on the east, Lorbeer Middle School and Mount Cavalry Lutheran Church and School on the south, and the Fall Creek private condominium community on the west.

45-Day Public Review Period

Diamond Bar residents and members of the public are encouraged to review the draft Supplemental Environmental Impact Report (SIR) for the proposed Diamond Bar Town Center Specific Plan. Copies are available for review at:

o Diamond Bar City Hall, 21810 Copley Drive

o Diamond Bar Library, 21800 Copley Drive

o Diamond Bar Town Center Specific Plan Project Website

Submitting Written Comments
Written comments regarding the environmental findings presented in the Draft SIR may be submitted by email or mail no later than 5:30 p.m. Oct. 10, 2025 to the City of Diamond Bar's Planning Manager Grace Lee at:

o Email:[email protected] or

o Mail: City of Diamond Bar, Planning Division, Attn: Planning Manager Grace Lee, 21810 Copley Drive, Diamond Bar, CA 91765

What Comes Next

Following the close of the Draft SIR public review period, a final environmental report will be prepared that will include responses to all substantiative comments received on the draft SIR.

For more information about the Supplemental Environmental Impact Report for the Diamond Bar Town Center Specific Plan, contact Planning Manager Grace Lee at 909-839-7032 or [email protected].