Looking at this story about a bid to make Indiana time-zone-uniform, I got to wondering again about the way time zones were set up. Checking out this map the zones by and large conform to state lines, with some obvious exceptions for states that are so wide they cross boundaries (Florida, Kentucky, Tennessee). But what’s with the twisty turnies of some of these borders? Why, when time zones were established (by whatever mechanism established them, I assume federal law), were the counties in the northwest and southwest corners of Indiana made Central when the rest of the state is Eastern? Why cut off that little corner of Texas and stick it in the Mountain zone instead of in Central with the rest of the state? Why four Kansas counties in Mountain with all the rest in Central? Why chop up the Dakotas the way they did? Why one Oregon county in Mountain and the rest in Western? And what the hell did they do to Idaho? Split the state in two with an extremely odd border. It’s not like the upper half of Idaho is so far west of the lower half that making the whole state Mountain would be so oddball, is it?
Well, as far as Idaho goes, it’s probably because most of central Idaho is filled with vast stretches of mostly uninhabited forest and wilderness. Southern Idaho is inhabited, and the panhandle is inhabited, but there’s not a lot in between. The panhandle, I believe, tends to identify more with the Pacific Northwest, so it does make some sense to put them in the same time zone.
Well the explanation for the northwest corner of Indiana that I’ve always heard is that they have more to do with Chicago than with the rest of Indiana, that it only makes sense to have both areas on the same time. Chicago seems pretty contiguous to me, and I’ve more than once wound up in that very part of Indiana when trying to get out of Chicago.
This site seems very informative regarding the Indiana oddity.
Basically, the answer is that localities (usually entire counties, but not always) determine what timezone they are in. And which timezone they are in is usually determined by what timezone the nearest large city is in. Take the Idaho and Oregon irregularities. Northern Idaho is in Pacific time, the same one that Spokane is in. Spokane is a central market/tv center for a fairly large area that includes northern Idaho. So it’s most convenient for northern Idaho to be in Pacific time. The same with most of Malheur County in Oregon, except this time the city is Boise and the timezone is Mountain.
Also note that the southern section of Malheur County is actually in Pacific timezone. I think that’s because that part uses Winnemucca NV as its market/tv center.
We’ve discussed this before. If you do an archive search on time zones, you’ll find several threads on it.