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Sonoma Public Infrastructure

Roads Division
County Of Sonoma › Development Services › Sonoma Public Infrastructure › Divisions › Roads › Data and Resources › Postmile System
Roads Division

Postmile System

Sonoma Public Infrastructure's offices are now located at 400 Aviation Blvd, Suite 100, Santa Rosa, CA 95403.

Postmile System Map

Legend

Bridge 4 Bridge MiC2 State or US Highway County Maintained Road County-Maintained

What is a postmile?

A postmile (AKA post mile) is a numerical value that identifies a specific linear location along a County road, based on its distance (in miles) from the beginning of the road (e.g. if you are at postmile 10.00, then postmile 11.00 is one mile up the road). All Sonoma County roads have designated beginning and ending post mile assignments.