California state route 146 still has a short eastern section connected to route 25. The signage has apparently been taken down, but it is still listed in the CalTrans postmile query tool.
The dirt portion of state route 173 is also still listed in the postmile query tool, even though it's gated off, probably permanently. Since some of us have actually driven it before it was closed, it should be listed somewhere, maybe as "historic". I suppose the same argument could be made for the northern end of route 39, although that's been closed to traffic since 1978.