Time in Idaho
- Benewah County
- Bonner County
- Boundary County
- Clearwater County
- Kootenai County (includes Coeur d'Alene)
- Latah County (includes Moscow)
- Lewis County
- Nez Perce County (includes Lewiston)
- Shoshone County
- Portion of Idaho County north of the Salmon River
- The towns of Burgdorf and Warren
An easy way to distinguish the line is that it essentially follows the line that divides Washington and Oregon. Idaho counties east of Washington observe Pacific Time, and Idaho counties east of Oregon observe Mountain Time.
For three decades or so in the middle of the twentieth century, Shoshone County had its own time arrangements; it was said to be "on permanent daylight time", so that in the winter the county had the same clock time as Montana and southern Idaho, but in the summer it had the same clock time as Spokane and northern Idaho.
The tz database version 2017c contains two time zones for Idaho:
|CC||Coordinates||TZ||Comments||UTC offset||UTC offset DST||Notes|
|US||+433649-1161209||America/Boise||Mountain Time - south Idaho & east Oregon||−07:00||−06:00|
- Prerau, David (2006). Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time. p. 91. ISBN 978-1-56025-796-7.
- "Time Zone Woe May Be Solved". Spokane Daily Chronicle. 1966-11-04. Retrieved 2016-05-31.