Sierra County, CA ZIP Codes & Directory
Complete postal guide for Sierra County, California. Featuring the official county seat of Downieville, largest municipality Loyalton, and serving 4 incorporated municipal entities.
Municipalities Located in Sierra County
Incorporated Cities, Towns, and Villages
Active USPS ZIP Codes in Sierra County
Standard delivery zones and geographic service boundaries
Frequently Asked Questions About Sierra County, CA
What is the county seat and largest city in Sierra County? ▾
The official county seat of Sierra County is Downieville, and its largest incorporated municipality by population is Loyalton.
How many cities, towns, and villages are in Sierra County? ▾
Sierra County encompasses 4 incorporated municipal entities, including 4 cities, 0 towns, and 0 villages.
What is the total population and land area of Sierra County? ▾
According to official U.S. Census Bureau data, Sierra County has a population of approximately 3,236 residents and spans an area of 953 square miles.
How many ZIP codes operate in Sierra County? ▾
There are 4 active USPS ZIP codes serving addresses within Sierra County, California.