Capital: Washington, D.C. · Four main time zones plus Alaska & Hawaii · large enough that "prayer times in the US" is really several regional stories, not one.
METHOD: ISLAMIC SOCIETY OF NORTH AMERICA (ISNA)The ISNA method uses a 15°/15° solar angle convention for Fajr and Isha, slightly narrower than the 18° angles common in the Muslim World League or Karachi methods — in practice this tends to produce a somewhat later Fajr and earlier Isha at the same location. But the more distinctive fact about the US is simply its size: spanning Eastern, Central, Mountain and Pacific time (plus Alaska and Hawaii further out), a flat list of city times without regional grouping would be genuinely confusing, since two cities showing similar clock-time schedules can sit thousands of kilometres apart.
The US spans four main time zones — Eastern, Central, Mountain and Pacific — plus Alaska and Hawaii, so a flat city list without noting the zone can be confusing; two cities can show similar clock-time prayer schedules despite being thousands of kilometres apart.
It refers to the solar angle below the horizon used to define Fajr and Isha — 15 degrees for both — slightly narrower than some other conventions, typically producing a later Fajr and earlier Isha than, for example, the Karachi or MWL methods at the same location.
It affects the clock label, not the underlying sun-based calculation — most of the US observes DST (except Arizona and Hawaii), so a city's prayer times will appear to shift by an hour each spring and fall along with the clock change.