IANA tz database · America/Indiana/Petersburg · zdump −v
Of every time zone in the contiguous United States, Pike County, Indiana changed its mind the most. Since railroad time arrived in 1883 it jumped between Central and Eastern zones six times — twice reversing within a single year — then sat frozen on Eastern Standard Time for 28 years while refusing to observe daylight saving at all. The line below is colored by which zone the county was in.
Railroad standard time replaces the county's local mean time (−5:49). Pike County starts life in the Central zone at −6:00 CST.
The county leaps to Eastern Standard Time (−5) — and skips daylight saving. Barely eighteen months later it reverses.
Pike County returns to the Central zone and resumes the normal CST/CDT sawtooth for another decade.
The county moves to Eastern Standard Time and stops moving — no spring-forward, no fall-back, a flat line at −5 for nearly three decades, in step with most of Indiana.
Indiana's statewide DST reform reshuffles counties. Pike lands back in Central with daylight saving — its final Central year ever.
Within a year it flips to Eastern once more and finally keeps normal daylight saving — the EST/EDT sawtooth every other Eastern county has run since 1966.