The county was founded in 1837 and is named after Robert Trimble. Trimble was a lawyer and jurist who served as Justice of the Kentucly Court of Appeals, U.S. District Judge of the U.S. District Court for the District of Kentucky and as an Associate Jutice for the U.S. Supreme Court. Its county seat is Bedford and has the counties of Jefferson, Carroll, Henry, Oldham and Clark (Indiana). The county had a total area of 156 square miles and has under 10,000 residents.