Assessor’s Parcel Viewer and Parcel Maps

Assessor Parcel Maps along with assessment and property related data can be accessed through Assessor Parcel Viewer.

Open Parcel Viewer

Disclaimer Notice
The data, information, and maps provided herein are derived from various sources and are dynamic and in an ongoing state of maintenance, correction and update, and are subject to verification by the user and/or Alameda County. The mapped data depicted herein does not constitute a legal survey. The County of Alameda makes no warranty, representation or guarantee as to the content, accuracy, timeliness or completeness of any of the information implied herein. The County of Alameda explicitly disclaims any representation and warranties, including, without limitation, the implied warranties of merchantability and fitness for a particular purpose.

The Parcel Viewer is the property of Alameda County and shall be used only for conducting the official business of Alameda County. No person shall use or permit the use of the Parcel Viewer for any purpose other than the conduct of official Alameda County business. “Use in the conduct of official Alameda County business” means using or operating the Parcel Viewer in the performance of or necessary to or in the course of the official duties and services of Alameda County. Prohibited uses include, but are not limited to, uses for political campaigns, personal matters, or profit.

About Assessor Parcel Maps

The Alameda County Assessor’s Office maintains assessor parcel maps for all properties in the county. These maps are used for assessment purposes and are an important resource for property owners, real estate professionals, and the public. Below are answers to commonly asked questions about parcel maps.

General Information

What are Assessor Parcel Maps?
Assessor parcel maps show parcel boundaries, parcel numbers (APNs), dimensions, acreage, street addresses, and related map references. They are compiled from recorded documents, government surveys, and other official records maintained by the county.
Are Assessor Parcel Maps legal documents?
No. Assessor parcel maps are prepared for assessment purposes only. They are not legal surveys and should not be used to determine exact property boundaries or resolve boundary disputes. For legal boundary determinations, you should consult a licensed land surveyor.
How can I view Assessor Parcel Maps?
You can view parcel maps online using our Assessor Parcel Viewer. Maps are also available for review in person at the Assessor’s Office during regular business hours.

Parcel Numbers

What is an Assessor Parcel Number (APN)?
An Assessor Parcel Number is a unique identification number assigned to every parcel of land in the county. The APN is used for assessment and tax purposes to identify individual properties.
When does a parcel number change?
Parcel numbers may change when parcels are subdivided, combined, or when boundaries are adjusted through recorded maps or deeds. Changes to parcel numbers typically become effective in the following tax year.
How long does it take to create a new parcel number?
The time required to create a new parcel number varies depending on the complexity of the recorded document. Please note that parcel map processing may be paused during May and June each year due to annual tax roll preparation.

Property Boundaries and Descriptions

Can the Assessor's Office tell me where my property boundaries are?
No. The Assessor’s Office cannot determine or verify exact property boundaries. Parcel maps are approximate representations for assessment purposes only. To determine actual property boundaries, you should hire a licensed land surveyor.
Where can I find the legal description of my property?
Legal descriptions of property appear on recorded deeds and other recorded documents. These documents are available through the Alameda County Clerk-Recorder’s Office.
Can I get information about easements on my property?
Easement information is typically found in recorded documents at the County Clerk-Recorder’s Office. The Assessor’s Office does not maintain comprehensive easement records.

Parcel Modifications

How do I combine or subdivide my property?

Property combines or subdivisions requires approval from your local city or county planning department. Contact your local planning department for information about the subdivision process, required permits, and fees.

GIS and Technical Questions

Why do parcel boundaries on the online map viewer not always match recorded documents?
Parcel boundaries displayed in the online viewer may shift slightly due to aerial photo overlays and the limitations of converting recorded document data to digital map formats. There may also be a processing delay of several weeks before newly recorded changes appear in the viewer.

Contact Us

For questions about parcel maps, please contact:

Phone: (510) 272-3787
Main Office: 1221 Oak Street, Room 145, Oakland, CA 94612
Public Lobby Hours: 9:00 AM to 4:30 PM, Monday through Friday (except holidays)
Online: Assessor Parcel Viewer

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