When a public offense is committed on the boundary of two (2) or more counties, or within five hundred (500) yards thereof, if the place where the crime is committed cannot be ascertained with reasonable certainty by the law enforcing officers of either county, or if a misdemeanor or infraction is committed in a city which is located in two (2) counties, then in any such event the venue is in either county. Provided however, that a prosecution in one (1) county shall be a bar to a prosecution for the same act or offense in the other county.
Idaho Code § 19-305