Field to Fork located in Red Bluff. Here is a quick quote from their website: "Field to Fork Tehama, LLC is a multi-farm CSA that provides members with a weekly box filled with vegetables,fruit and protein that are currently in season."
This link to searching by zip code if you are out exploring new areas or staying local. They didn't have every farmers market listed that I have visited over the last few years but they had a good place to start.
Shasta Growers Association. This link will provide information on Shasta Growers and where their growers can be found locally, locations and times.
Tehama County page for local farmers markets.
Duivenvoorden Farms, Cottonwood Ca. They have several events that hopefully will return next year when things have settled down. Check out their website, also under YouTube is a video field trip they made for preschoolers and Kindergartners that couldn't have their field trips this year.