APM: 0 Location: SR 139 and SR 299, Modoc Cty Reassurance shield as 139 joins 299. The two routes use 299’s mileposts, owing to 299’s time as a U.S. route. APM: 0 Location: Main St and Walnut St, Adin A few feet later, we’ll enter Adin. APM: 0 Location: Main St and Juniper St, Adin Reassurance shield as … Continue reading California State Route 299, SR 139 to SR 139