Depending on where in Shasta County you are, there may be existing commercial fiber providers. There are two traditional telephone providers that cover the county, AT&T (west of Palo Cedro) and Frontier (Palo Cedro and east) of Palo Cedro, and they both offer fiber service to locations in their footprint. There is also fiber service available from Spectrum in the Redding and Anderson area (and maybe Palo Cedro). I have no affiliation with and am not endorsing any of these providers. None of them seem to be very responsive, and their corporate structures can’t seem to find Shasta County on a map, but if you are persistent and dedicated, you might be able to find someone to sell you a product. I have worked with all of these providers on fiber Ethernet circuits, and they are reliable and the local techs are good, so if you need it and they can do it, it is better than nothing.

For AT&T, you can start here: https://www.att.com/smallbusiness/explore/quickflow/business-internet/ For fiber, you want “AT&T Dedicated Internet”, otherwise it will be crappy 6Mb/768kb DSL. It will also cost as much as your rent, and if you are not already next to their fiber, it will probably have construction costs.

For Frontier, you can start here: https://www.getfrontier.com/fiberoffer-c#serviceability-form For fiber, you will probably have to talk to someone, their web site seems to only give DSL results or “Nice going. You’re already a customer.” for sites that already have fiber. It will also cost as much as your rent, or more, and will have construction costs.

For Spectrum, you can start here: https://enterprise.spectrum.com/landing/2020/fiber/online/is-fia1.html You will definitely have to talk to someone, they only provide a contact form, no address lookup. If you are in their coverage area, they may be your most cost effective option. They also offer business cable Internet access.