Deputy U.S. Marshal Raylan Givens is something of a 19th century-style officer in modern times, whose unconventional enforcement of justice makes him a target with criminals and a problem for his superiors in the U.S. Marshals Service. As a result of an eager but "justified" shooting of a Miami fugitive while on assignment in Florida, Givens is reassigned to Lexington, Kentucky, in a district that includes his hometown of Harlan, a rural mining town in the east of the state.
Timothy Olyphant (Hitman the movie) plays the lead, with a great support cast. There's some really great chemistry in the rivalry between Raylan Givens and Boyd Crowder (Walton Goggins). The characters are varied and even those on the periphery have decent depth.
The show gets better with each season, number 3 having started up only recently.
SPOILERS HIDDEN; Do not read unless you're up to date