Idaho Counties

The Southern part of Idaho (except Panhandle and Clearwater Regions) fall in the Mountain Time Zone, which is 7 hours behind Greenwich Mean Time (GMT), while the Northern part of Idaho (Panhandle and Clearwater Regions) fall in the Pacific Time Zone, which is 8 hours behind GMT.

Counties of Idaho and their Time Zones

Idaho is divided into political jurisdictions designated as counties.

IDAHO COUNTIES
County name	County seat	Time Zone	Year founded	Population
Ada County	Boise	Mountain Time Zone	1864	300,904
Adams County	Council	Mountain Time Zone	1911	3,476
Bannock County	Pocatello	Mountain Time Zone	1893	75,565
Bear Lake County	Paris	Mountain Time Zone	1893	6,411
Benewah County	St. Maries	Pacific Time Zone	1915	9,171
Bingham County	Blackfoot	Mountain Time Zone	1885	41,735
Blaine County	Hailey	Mountain Time Zone	1895	18,991
Boise County	Idaho City	Mountain Time Zone	1864	6,670
Bonner County	Sandpoint	Pacific Time Zone	1907	36,835
Bonneville County	Idaho Falls	Mountain Time Zone	1911	82,522
Boundary County	Bonners Ferry	Pacific Time Zone	1915	9,871
Butte County	Arco	Mountain Time Zone	1917	2,899
Camas County	Fairfield	Mountain Time Zone	1917	991
Canyon County	Caldwell	Mountain Time Zone	1891	131,441
Caribou County	Soda Springs	Mountain Time Zone	1919	7,304
Cassia County	Burley	Mountain Time Zone	1879	21,416
Clark County	Dubois	Mountain Time Zone	1919	1,022
Clearwater County	Orofino	Pacific Time Zone	1911	8,930
Custer County	Challis	Mountain Time Zone	1881	4,342
Elmore County	Mountain Home	Mountain Time Zone	1889	29,130
Franklin County	Preston	Mountain Time Zone	1913	11,329
Fremont County	St. Anthony	Mountain Time Zone	1893	11,819
Gem County	Emmett	Mountain Time Zone	1915	15,181
Gooding County	Gooding	Mountain Time Zone	1913	14,155
Idaho County	Grangeville	Pacific Time Zone	1861/1864	15,511
Jefferson County	Rigby	Mountain Time Zone	1913	19,155
Jerome County	Jerome	Mountain Time Zone	1919	18,342
Kootenai County	Coeur d'Alene	Pacific Time Zone	1864	108,685
Latah County	Moscow	Pacific Time Zone	1886	34,935
Lemhi County	Salmon	Mountain Time Zone	1869	7,806
Lewis County	Nezperce	Pacific Time Zone	1911	3,747
Lincoln County	Shoshone	Mountain Time Zone	1895	4,044
Madison County	Rexburg	Mountain Time Zone	1914	27,467
Minidoka County	Rupert	Mountain Time Zone	1913	20,174
Nez Perce County	Lewiston	Pacific Time Zone	1861/1864	37,410
Oneida County	Malad City	Mountain Time Zone	1864	4,125
Owyhee County	Murphy	Mountain Time Zone	1863	10,644
Payette County	Payette	Mountain Time Zone	1917	20,578
Power County	American Falls	Mountain Time Zone	1913	7,538
Shoshone County	Wallace	Pacific Time Zone	1864	13,771
Teton County	Driggs	Mountain Time Zone	1915	5,999
Twin Falls County	Twin Falls	Mountain Time Zone	1907	64,284
Valley County	Cascade	Mountain Time Zone	1917	7,651
Washington County	Weiser	Mountain Time Zone	1879	9,977

Two counties were first designated as such by the Washington Territorial Legislature in 1861; they were subsequently re-designated as Idaho counties in 1864