Callahan is an unincorporated community

Unincorporated area

In law, an unincorporated area is a region of land that is not a part of any municipality.To "incorporate" in this context means to form a municipal corporation, a city, town, or village with its own government. An unincorporated community is usually not subject to or taxed by a municipal government...

 in Siskiyou County

Siskiyou County, California

Siskiyou County is a county located in the far northernmost part of the U.S. state of California, in the Shasta Cascade region on the Oregon border. Yreka is the county seat. Because of its substantial natural beauty, outdoor recreation opportunities, and Gold Rush era history, it is an important...

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Callahan is located on California State Route 3 11.5 miles (18.5 km) south-southeast of Etna

Etna, California

Etna is a city in the Scott Valley area of Siskiyou County, California, United States. The population was 737 at the 2010 census, down from 781 at the 2000 census.-Geography:...

. Callahan has a post office

Post office

A post office is a facility forming part of a postal system for the posting, receipt, sorting, handling, transmission or delivery of mail.Post offices offer mail-related services such as post office boxes, postage and packaging supplies...

 with ZIP code

ZIP Code

ZIP codes are a system of postal codes used by the United States Postal Service since 1963. The term ZIP, an acronym for Zone Improvement Plan, is properly written in capital letters and was chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the...

96014. The post office opened as Callahan's Ranch in 1858 and changed its name to Callahan in 1892. The community was named after M.B. Callahan, who opened a travelers' stop in the community in 1851.