Thanks for everybody's input. I gather that the circuits referred to were sometimes rather large (geographically speaking), so if more than one county is involved, tracing their current whereabouts might be rather difficult. Still, they ought to be in the records office of one of the counties involved. Sometimes I think genealogy is rather like solving complex algebraic problems, with a series of equations containing umpteen variables and only one (usually far from obvious) way of solving the problem.