Aha! You're right: That's in section (g) of the same statute. (g) Municipalities on boundary line. All municipalities located upon the zone boundary line described in this section are in the mountain standard time zone, except Murdo, S. Dak., which is in the central standard time zone. It's interesting that it calls out Murdo as being in Central, as Murdo is not along the boundary line. It's clear into the Central time zone anyway. You'd think it would say something about Fort Pierre. So Fort Pierre then is indeed officially in the Mountain time zone, but chooses to observe Central - that should be in the commentary for sure. Cheers!-Matt From: stevejones@ontimezone.com Date: Thu, 24 Dec 2015 19:41:15 -0600 Subject: Re: [tz] FYI Time zone used in Fort Pierre SD USA To: mj1856@hotmail.com CC: rickmcdermid@shaw.ca; tz@iana.org Matt: The Central/Mountain time zone boundary language is slightly confusing, and you have fallen into a common misinterpretation. If you read farther into the text of the boundary description, which may appear to bisect the city of Fort Pierre, you will find this: ""...municipalities located upon the zone boundary line described in this section are in the mountain standard time zone..."." Refer to my previous post for more detail, especially related to the fact that the entire area observes central time despite the federal definition. Steve Jones On Thu, Dec 24, 2015 at 7:13 PM, Matt Johnson <mj1856@hotmail.com> wrote: Actually, the city's representative is incorrect, as Stanley County is not entirely in the Mountain time zone. Part of it is officially in the Central time zone. The official time zone boundary, as described in CFR 49 § 71.7(b) is as follows:http://www.ecfr.gov/cgi-bin/text-idx?node=se49.1.71_17 (b) South Dakota. From the junction of the North Dakota-South Dakota boundary with the Missouri River southerly along the main channel of that river to the crossing of the original Chicago & North Western Railway near Pierre; thence southwesterly to the northern boundary of Jones County at the northeast corner of the NE 1, Sec. 6, T. 2 N., R. 30 E.; thence west along the northern boundary of Jones County; thence south along the western boundaries of Jones, Mellette and Todd Counties to the South Dakota-Nebraska boundary. The rail crossing mentioned in the statute is the bridge that is just north of where US Route 14 intersects the Missouri River. The line then proceeding southwesterly actually bisects the city of Fort Pierre into two. The southern half officially falls into the Central time zone. The northern half officially falls into the Mountain time zone, but it is rare for a city to observe such a split. Since the surrounding cities are all in the Central zone, it makes sense that Central is the one observed by the entire city. Some supporting pictures: Fort Pierre and Pierre city boundaries in Yellow. Railway in Black, Time zone boundary from tz_world in Red (though slightly misaligned in this pic, mostly accurate.)http://i.imgur.com/kTzKXgD.png Zoomed out, showing county boundaries in light blue, you can see Stanley county divided by the line described in the statute.http://i.imgur.com/aCWbxds.png WRT the TZDB, unless there's a distinct history of which time zones were observed in Fort Pierre, then it doesn't warrant a distinct entry of its own, though it could be mentioned in commentary of the America/Chicago time zone. Cheers!-Matt Date: Wed, 23 Dec 2015 16:11:17 -0700 From: rickmcdermid@shaw.ca To: tz@iana.org Subject: [tz] FYI Time zone used in Fort Pierre SD USA FYI, see below for some information regarding the City of Fort Pierre SD USA time zone. It looks like Fort Pierre and the surrounding Stanley County unofficially use Central Time.. Rick McDermid, Chilliwack BC Canadarickmcdermid@shaw.ca From: "Administration" <Admin1@fortpierre.com> To: "RICK MCDERMID" <rickmcdermid@shaw.ca> Sent: Monday, December 21, 2015 1:46:47 PM Subject: RE: Question about time in Fort Pierre Hi Rick Yes, Fort Pierre is technically located in the Mountain time zone as is the rest of Stanley County. Most of Stanley County and Fort Pierre uses the Central time zone due to doing most of their business in Pierre so it simplifies schedules. I have lived in Stanley County all my life and it has been that way since I can remember. (43 years!) I hope this helps you. If you have any further questions let me know. Thanks! Kelly City of Fort Pierre From: RICK MCDERMID [mailto:rickmcdermid@shaw.ca] Sent: Monday, December 21, 2015 3:22 PM To: admin1@fortpierre.com Subject: Question about time in Fort Pierre Hello. I'm updating some geographic data, and I have a question about your time zone. I understand that Fort Pierre is officially on Mountain time, while Pierre is on Central time. However, based on your location right across the river, it looks like you might actually use the same time as Pierre. Could you tell me which time zone you use? If you do follow Central time like Pierre, do you know if the rest of Stanley County does likewise? Do you know if there is any history to the issue? If you do go by the unofficial Central time I will pass the info along to www.iana.org, a non-profit which (among other things) publishes a global time zone database used widely for computer apps and the like. Thanks for your help. Rick McDermid, Chilliwack BC Canada rickmcdermid@shaw.ca