L.A. County's Regional Planning Commission Celebrates 100 Years of Service

The first planning commissioners were appointed by the Board of Supervisors in 1923, making the Regional Planning Commission the oldest county planning commission in the United States.

2 minute read

April 25, 2023, 12:00 PM PDT

By Clement Lau


Vintage 1929 map of Los Angeles

County of Los Angeles / Map of Los Angeles, 1929.

In 2023, the Los Angeles County Regional Planning Commission (RPC) celebrates its 100th anniversary. In late 1922, the L.A. County Board of Supervisors created the Commission with staff to coordinate land use planning within the county. The first regional planning commissioners were appointed by the Board in early 1923. This makes the RPC the oldest county planning commission in the U.S.

The RPC acts as an advisory body to the Board of Supervisors on all planning matters. The commissioners administer provisions of the State Planning Law (Title 7, Division I, of the Government Code), the State Subdivision Map Act, California Environmental Quality Act, and the LA County ordinances affecting planning such as the County Zoning Ordinance and Subdivision Ordinance. They advise on planning policies and conduct regular public hearings and meetings. RPC consists of five Commissioners which are appointed to four-year terms by the Board of Supervisors.

To commemorate and celebrate this significant milestone, the Department of Regional Planning (DRP) created a StoryMap which summarizes the fascinating history and major accomplishments of the RPC and DRP. For example, the inaugural RPC immediately got to work on the issues of the day and started the development of a zoning code early on.  The Board of Supervisors adopted what became the first county zoning code in the nation on September 12, 1927. Following adoption of the zoning code, the RPC initiated the process of creating precise zoning plans for many unincorporated areas and places.

Friday, April 21, 2023 in Los Angeles County Department of Regional Planning

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 11, 2025 - Diana Ionescu

Metrorail train pulling into newly opened subterranean station in Washington, D.C. with crowd on platform taking photos.

Congressman Proposes Bill to Rename DC Metro “Trump Train”

The Make Autorail Great Again Act would withhold federal funding to the system until the Washington Metropolitan Area Transit Authority (WMATA), rebrands as the Washington Metropolitan Authority for Greater Access (WMAGA).

June 2, 2025 - The Hill

Large crowd on street in San Francisco, California during Oktoberfest festival.

The Simple Legislative Tool Transforming Vacant Downtowns

In California, Michigan and Georgia, an easy win is bringing dollars — and delight — back to city centers.

June 2, 2025 - Robbie Silver

Bird's eye view of studio apartment design.

In These Cities, Most New Housing is Under 441 Square Feet

With loosened restrictions on “micro-housing,” tiny units now make up as much as 66% of newly constructed housing.

1 hour ago - Smart Cities Dive

Man in teal shirt opening door to white microtransit shuttle with cactus graphics and making inviting gesture toward the camera.

Albuquerque’s Microtransit: A Planner’s Answer to Food Access Gaps

New microtransit vans in Albuquerque aim to close food access gaps by linking low-income areas to grocery stores, cutting travel times by 30 percent and offering planners a scalable model for equity-focused transit.

June 13 - U.S. Department Of Transportation

Group of people at table set ouf with picnic food on street during a neighborhood block party.

This City Will Pay You to Meet Your Neighbors

A North Kansas City grant program offers up to $400 for residents to throw neighborhood block parties.

June 13 - The Kansas City Star