Geographical boundaries for the continental US tz zones

rlaw at rlaw at
Wed Jul 18 16:07:45 UTC 2007

----- Original Message -----
From: Paul Eggert <eggert at CS.UCLA.EDU>

> I send my comments to your US timezone map directly to the TZ list
> since I
> think it could be of common interest in the list and also to urge
> members to
> send comments where appropriate.

I've put all of my findings about the limits of U.S. time zones (past
and present) online at  It's all
verbal description.  For example:

> * Idaho county split (Idaho state)
> I have a northern and southern part of Idaho county, which I got from
> another timezone map (possibly Manifold map). This indicates that the
> southern part of Idaho county is on America/Boise time while the
> northernpart is on America/Los_Angeles.

I have "Idaho county north of the Salmon River" on Pacific Time.

> * Sioux county North Dakota
> Tz database states "part of Sioux county" and that is exactly what
> you have
> included, splitting it around Latitude 46 Longitude -101.34. Where
> did you
> get shis from? I have included all Sioux county being on same time,
> but that
> most be wrong.

I have "Sioux county west of ND route 31" on Mountain Time.

Gwillim Law

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