Q May the county invest excess funds in state or federal bonds if the county is able to invest in one-year certificates of deposit?

A No. Section 19-9-29 requires the county to invest excess funds in certificates of deposit with or through county depositories to the extent that such investments can be made.
Any funds that cannot be invested in this manner must be invested in certificates of deposit with or through state depositories located in the county. Only funds that cannot be invested in either of these ways may be invested in state or federal bonds. (Attorney General’s Opinion to Sanders dated October 28, 2011)