Most US regions change clocks on the second Sunday in March and first Sunday in November. Hawaii and most of Arizona do not; the Navajo Nation is an exception. The clocks below cover major inhabited zones, not every US territory.
Time zones
New York: America/New_York
Chicago: America/Chicago
Denver: America/Denver
Los Angeles: America/Los_Angeles
Phoenix: America/Phoenix
Anchorage: America/Anchorage
Honolulu: Pacific/Honolulu
Fixed-date observances
Non-exhaustive selection; excludes substitute and moved holidays.