Transportation and Public Works is now Sonoma Public Infrastructure - Website updates coming soon!
Postmile System Map
|Bridge||State or US Highway||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.