In the years 1856 to 1858, William Byars carried the Federal mail once a week, on horseback, in both directions over the Siskiyou Trail. This mail route covered 187 miles, and connected 13 post offices from Oakland, Oregon Territory, to Yreka. Byars was just 17 years old when he took the job of mail rider.
Four mail routes started in Oakland, O.T., where all the mail arriving from the four riders was dumped on the floor and sorted out for each route. The horseback mail was carried just prior to the beginning of the daily stagecoach mail service.
The only two post offices in California that were part of Byar's route, were Henley and Yreka. The Henley post office was on the west side of Cottonwood Creek, which was crossed by a ford, there was no bridge. From there the route went up the Klamath River about a mile where a ferry crossed the river. Then Byars went over the hills to Surprise Valley, along its west margin to the crossing of the Shasta River and then to Yreka. The name Surprise Valley for Shasta Valley is a real surprise to current residents.
from The Siskiyou County Museum and Historical Society