Idaho Railway Post Offices

Chicago Milwaukee Saint Paul & Pacific

Routes on the CMSP&P (Milwaukee Road) Main Line crossing northern Idaho

RPO	Dates	Comments
MISSOULA & ELLENSBURG	1910-1914	ED/WD at MALDEN
BUTTE & SEATTLE	1914-1955	ED/WD at SPOKANE
		WD discontinued 1953

Routes on the Elk River Branch of the CMSP&P (Milwaukee Road) Main Line

RPO	Dates	Comments
SAINT MARIES & ELK RIVER	1911-1913
SPOKANE & ELK RIVER	1913-1914
SAINT MARIES & ELK RIVER	1914-1916
SPOKANE & ELK RIVER	1916-1917
SAINT MARIES & ELK RIVER	1917-1931

Route on the Spokane Bypass from the CMSP&P (Milwaukee Road) Main Line

RPO	Dates	Comments
PLUMMER & MARENGO	1915-1918

Great Northern Main Line

Routes on the Great Northern Main Line crossing northern Idaho

RPO	Dates	Comments
KALISPELL & SPOKANE	1893-1896
HAVRE & SPOKANE	1896-1909
SAINT PAUL & HAVRE plus HAVRE & SPOKANE redivided into SAINT PAUL & GLASGOW plus GLASGOW & SPOKANE
GLASGOW & SPOKANE	1909-1909	ED/WD at WHITEFISH
SAINT PAUL & GLASGOW plus GLASGOW & SPOKANE redivided back into SAINT PAUL & HAVRE plus HAVRE & SPOKANE
HAVRE & SPOKANE	1909-1917
SAINT PAUL & HAVRE plus HAVRE & SPOKANE redivided into SAINT PAUL & WILLISTON plus WILLISTON & SPOKANE
WILLISTON & SPOKANE	1917-1934	ED/WD at SHELBY
WILLISTON & SPOKANE plus SPOKANE & SEATTLE combined into WILLISTON & SEATTLE
WILLISTON & SEATTLE	1934-1967	ED/MD at SHELBY
		MD/WD at SPOKANE
		WD discontinued 1971

Northern Pacific Main Line

Routes on the Northern Pacific Main Line crossing northern Idaho

RPO	Dates	Comments
PEND D'OREILLE & WALLULA	1882-1883
PEND D'OREILLE & WALLULA and WALLA WALLA & PORTLAND merged into HELENA & PORTLAND
HELENA & PORTLAND	1883-1883
HELENA & PORTLAND divided into HELENA & SPOKANE FALLS plus SPOKANE FALLS & PORTLAND
HELENA & SPOKANE FALLS	1883-1884
HELENA & SPOKANE FALLS plus SPOKANE FALLS & PORTLAND redivided into HELENA & HERON plus HERON & WALLULA plus WALLULA & PORTLAND
HERON & WALLULA	1884-1885
HELENA & HERON plus HERON & WALLULA plus WALLULA & PORTLAND combined back into HELENA & PORTLAND
HELENA & PORTLAND	1885-1888	route changed 1887
		then ED/WD at SPOKANE FALLS
route merged with PASCO & CLE ELUM plus TACOMA & PORTLAND and changed from via THE DALLES to via TACOMA
MANDAN & HELENA plus HELENA & PORTLAND (via TACOMA) redivided into MANDAN & SPOKANE FALLS plus SPOKANE FALLS & PORTLAND
MANDAN & SPOKANE FALLS	1888-1889	ED/MD at FORSYTH
		MD/WD at HELENA
SAINT PAUL & MANDAN plus MANDAN & SPOKANE FALLS redivided into SAINT PAUL & HELENA plus HELENA & SPOKANE FALLS
HELENA & SPOKANE FALLS	1889-1891
HELENA & SPOKANE	1891-1899
SAINT PAUL & HELENA plus HELENA & SPOKANE combined into SAINT PAUL & SPOKANE
SAINT PAUL & SPOKANE	1899-1909	1D/2D at JAMESTOWN
		2D/3D at MILES CITY
		3D/4D at HELENA
SAINT PAUL & SPOKANE divided into SAINT PAUL & MILES CITY plus MILES CITY & SPOKANE
MILES CITY & SPOKANE	1909-1934	ED/WD at HELENA
MILES CITY & SPOKANE plus SPOKANE PASCO & SEATTLE combined into MILES CITY & SEATTLE
MILES CITY & SEATTLE	1934-1967	ED/MD at HELENA or BUTTE
		MD/WD at SPOKANE

Northern Pacific Branch Lines

Routes on the Genesee and Lewiston Branches of the Northern Pacific Main Line

RPO	Dates	Comments
SPOKANE FALLS & GENESEE	1888-1891
SPOKANE & GENESEE	1891-1891
SPOKANE & JULIAETTA	1891-1896
route via MOSCOW
SPOKANE & GENESEE	1896-1898
SPOKANE & LEWISTON	1898-1955
route via MOSCOW and JULIAETTA
route discontinued at same time as LEWISTON & AYER (See Camas Prairie routes) and MOSCOW & AYER (see Oregon Washington / Union Pacific routes)
PULLMAN & GENESEE	1902-1907	supplemental route 1 of 2
supplemental route established concurrent with SPOKANE & LEWISTON
SPOKANE & GENESEE	1907-1916	supplemental route 2 of 2
supplemental route discontinued concurrent with SPOKANE & LEWISTON

Routes on the Wallace Branch of the Northern Pacific Main Line

RPO	Dates	Comments
BURKE & SPOKANE FALLS	1889-1890
WALLACE & SPOKANE FALLS	1890-1890
MULLAN & SPOKANE FALLS	1890-1891
route superseded by WALLACE & TEKOA (see Oregon Washington / Union Pacific routes)
MISSOULA & WALLACE	1900-1941
route established concurrent with WALLACE & TEKOA (see Oregon Washington / Union Pacific routes)

Route on the Coeur d'Alene Branch of the Northern Pacific Main Line

RPO	Dates	Comments
COEUR D'ALENE & SPOKANE	1902-1904

OSL / UP Main Line

Routes on the Oregon Short Line / Union Pacific Main Line crossing southern Idaho

RPO	Dates	Comments
GRANGER & SHOSHONE	1883-1884
GRANGER & ONTARIO STATION	1884-1884
GRANGER & HUNTINGTON	1884-1884
GRANGER & WEISER STATION	1884-1884
GRANGER & HUNTINGTON	1884-1886
GREEN RIVER & HUNTINGTON	1886-1890
CHEYENNE & HUNTINGTON	1890-1899
CHEYENNE & HUNTINGTON plus HUNTINGTON & PORTLAND redivided into CHEYENNE & POCATELLO plus POCATELLO & PORTLAND
CHEYENNE & POCATELLO	1899-1917	divided route east of POCATELLO 1 of 3
RAWLINS & POCATELLO	1917-1917	divided route east of POCATELLO 2 of 3
GREEN RIVER & POCATELLO	1917-1934	divided route east of POCATELLO 3 of 3
GREEN RIVER & POCATELLO plus POCATELLO & BAKER plus BAKER & PORTAND combined into GREEN RIVER & PORTLAND
POCATELLO & PORTLAND	1899-1917	divided route west of POCATELLO 1 of 2
POCATELLO & PARMA		short run of POCATELLO & PORTLAND
POCATELLO & PORTLAND divided into POCATELLO & BAKER plus BAKER & PORTLAND
POCATELLO & BAKER	1917-1934	divided route west of POCATELLO 2 of 2
GREEN RIVER & POCATELLO plus POCATELLO & BAKER plus BAKER & PORTAND combined into GREEN RIVER & PORTLAND
GREEN RIVER & PORTLAND	1934-1967	ED/MD at POCATELLO
		MD/WD at BAKER

OSL / UP Branch Lines

Routes on the Ketchum Branch of the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
KETCHUM & SHOSHONE	1884-1893
KETCHUM & SHOSHONE	1908-1942

Routes on the Boise Branch of the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
BOISE & NAMPA	1896-1908
BOISE & WEISER	1908-1909
BOISE & HUNTINGTON	1909-1916
BOISE & NAMPA	1916-1917
POCATELLO & BOISE	1911-1914	supplemental route
supplemental route established and discontinued concurrent with BOISE & HUNTINGTON and POCATELLO & PORTLAND (see Main Line)
POCATELLO & BOISE portion east of MINIDOKA plus MINIDOKA & BUHL (see Buhl Branch) combined into POCATELLO & BUHL (see Buhl Branch)

Routes on the Buhl Branch of the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
MINIDOKA & TWIN FALLS	1905-1908
MINIDOKA & BUHL	1908-1914
POCATELLO & BOISE portion east of MINIDOKA (see Boise Branch) plus MINIDOKA & BUHL combined into POCATELLO & BUHL
POCATELLO & BUHL	1914-1930
MINIDOKA & BUHL	1930-1955

Routes on the Shoshone Bypass from the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
MINIDOKA & BLISS	1913-1913
RUPERT & BLISS	1913-1919
MINIDOKA & BLISS	1919-1920
RUPERT & BLISS	1920-1921

Route on the Hill City Branch of the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
SHOSHONE & HILL CITY	1913-1917
route established and discontinued concurrent with KETCHUM & SHOSHONE (see Ketchum Branch)

Route on the McCall Branch of the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
MCCALL & NAMPA	1914-1948

Route on the Rogerson Branch of the Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
TWIN FALLS & ROGERSON	1915-1927
route established and discontinued concurrent with POCATELLO & BUHL (see Buhl Branch)

Oregon Washington / UP Branch Lines

Routes on the Moscow Branch of the Oregon Washington (Oregon Washington Railway & Navigation Company) / Union Pacific Main Line

RPO	Dates	Comments
MOSCOW & PALOUSE JUNCTION	1886-1887
MOSCOW & CONNELL	1887-1888
route superseded by FARMINGTON & PENDLETON
MOSCOW & HAAS	1926-1951
MOSCOW & AYER	1951-1955
route discontinued at same time as LEWISTON & AYER (see Camas Prairie routes) and SPOKANE & LEWISTON (see Northern Pacific routes)

Routes on the Wallace Branch of the Oregon Washington (Oregon Washington Railway & Navigation Company) / Union Pacific Main Line

RPO	Dates	Comments
WALLACE & TEKOA	1891-1892
route preceded by MULLAN & SPOKANE FALLS (see Northern Pacific routes)
MULLAN & TEKOA	1892-1893
WALLACE & TEKOA	1893-1896
WALLACE & SPOKANE	1896-1896
WALLACE & TEKOA	1896-1897
WALLACE & SPOKANE	1897-1899
WALLACE & TEKOA	1899-1906
WALLACE & SPOKANE	1906-1910
WALLACE & HARRISON	1910-1911
WALLACE & SPOKANE	1911-1955

Utah Northern / OSL / UP Main Line

Routes on the Utah Northern / Oregon Short Line / Union Pacific Main Line crossing eastern Idaho

RPO	Dates	Comments
FRANKLIN & OGDEN	1874-1880	AGT
TERMINUS & OGDEN	1880-1880	AGT
		TERMINUS in Idaho then Montana
RED ROCK & OGDEN	1880-1881	AGT
TERMINUS & OGDEN	1881-1882	AGT
		TERMINUS in Montana
BUTTE CITY & OGDEN	1882-1882	AGT then RPO
DEER LODGE CITY & OGDEN	1882-1883
GARRISON JUNCTION & OGDEN	1883-1883
GARRISON & OGDEN	1883-1885
GARRISON & OGDEN divided into GARRISON & BUTTE CITY plus BUTTE CITY & OGDEN
BUTTE CITY & OGDEN	1885-1894	route changed 1891
route changed from via PRESTON and FRANKLIN to via WESTON
BUTTE & OGDEN	1894-1897
BUTTE & SALT LAKE CITY	1897-1917
BUTTE & SALT LAKE CITY divided into BUTTE & SPENCER plus SPENCER & SALT LAKE CITY
BUTTE & SPENCER	1917-1918	divided route north of SPENCER
SPENCER & SALT LAKE CITY	1917-1918	divided route south of SPENCER
BUTTE & SPENCER plus SPENCER & SALT LAKE CITY combined back into BUTTE & SALT LAKE CITY
BUTTE & SALT LAKE CITY	1918-1967	ND/SD at POCATELLO

Utah Northern / OSL / UP Branch Lines

Routes on the Preston Branch of the Utah Northern / Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
PRESTON & OGDEN	1891-1893
route established when BUTTE CITY & OGDEN changed from via PRESTON and FRANKLIN to via WESTON (see Main Line)
PRESTON & CACHE JUNCTION	1893-1893
PRESTON & OGDEN	1893-1897
PRESTON & OGDEN plus OGDEN & SALT LAKE CITY combined into PRESTON & SALT LAKE CITY
PRESTON & SALT LAKE CITY	1897-1897
route discontinued when BUTTE & OGDEN extended into BUTTE & SALT LAKE CITY (see Main Line)
PRESTON & SALT LAKE CITY	1907-1918
route reestablished concurrent with BUTTE & SALT LAKE CITY (see Main Line) and MALAD CITY & SALT LAKE CITY (see Malad City Branch)
PRESTON & CACHE JUNCTION	1918-1943
route discontinued at same time as MALAD CITY & BRIGHAM (see Malad City Branch)

Routes on the Victor Branch of the Utah Northern / Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
SAINT ANTHONY & IDAHO FALLS	1900-1903
SAINT ANTHONY & SALT LAKE CITY	1903-1906
ASHTON & IDAHO FALLS	1906-1907
MARYSVILLE & IDAHO FALLS	1907-1909
MARYSVILLE & POCATELLO	1909-1912
ASHTON & POCATELLO	1912-1914
ASHTON & SALT LAKE CITY	1914-1916
VICTOR & SALT LAKE CITY	1916-1917
VICTOR & OGDEN	1917-1919
VICTOR & IDAHO FALLS	1919-1941
VICTOR & POCATELLO	1941-1946
VICTOR & IDAHO FALLS	1946-1956
ASHTON & VICTOR	1914-1915	supplemental route
supplemental route established concurrent with ASHTON & POCATELLO and discontinued concurrent with ASHTON & SALT LAKE CITY

Routes on the Mackay Branch of the Utah Northern / Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
BLACKFOOT & MACKAY	1902-1904
POCATELLO & MACKAY	1904-1904
BLACKFOOT & MACKAY	1904-1937
SALMON & BLACKFOOT	1937-1940	train and bus route
star route from SALMON to MACKAY
BLACKFOOT & MACKAY	1940-1942

Routes on the Malad City Branch of the Utah Northern / Oregon Short Line / Union Pacific Main Line

RPO	Dates	Comments
MALAD CITY & SALT LAKE CITY	1906-1914
route established concurrent with BUTTE & SALT LAKE CITY (see Main Line) and SAINT ANTHONY & SALT LAKE CITY (see Victor Branch)

MALAD CITY & BRIGHAM 1914-1921 MALAD CITY & SALT LAKE CITY 1921-1932 MALAD CITY & BRIGHAM 1932-1943 route discontinued at same time as PRESTON & CACHE JUNCTION (see Preston Branch)

Short Lines

Routes on the Camas Prairie Short Line

RPO	Dates	Comments
Stites Branch:
STUART & LEWISTON	1900-1901
STITES & LEWISTON	1901-1955
route discontinued at same time as other Camas Prairie routes
Grangeville Branch:
VOLLMER & LEWISTON	1908-1909
GRANGEVILLE & LEWISTON	1909-1955
route discontinued at same time as other Camas Prairie routes
Riparia Branch:
LEWISTON & RIPARIA	1908-1925
LEWISTON & RIPARIA	1927-1928
LEWISTON & HAAS	1928-1933
LEWISTON & RIPARIA	1933-1954
LEWISTON & AYER	1954-1955
route discontinued at same time as MOSCOW & AYER (see Oregon Washington / Union Pacific routes) and SPOKANE & LEWISTON (see Northern Pacific routes) and other Camas Prairie routes

Routes on the Pacific & Idaho Northern / Union Pacific Short Line

RPO	Dates	Comments
COUNCIL & WEISER	1903-1907
EVERGREEN & WEISER	1907-1911
NEW MEADOWS & WEISER	1911-1937
GRANGEVILLE & WEISER	1937-1950	train and bus route
star route from GRANGEVILLE to NEW MEADOWS

Routes on the Spokane & Inland Empire / Spokane Coeur d'Alene & Palouse Short Line

RPO	Dates	Comments
Coeur d'Alene Branch:
COEUR D'ALENE & SPOKANE	1907-1915	electric trolley route
HAYDEN LAKE & SPOKANE	1915-1917	electric trolley route
COEUR D'ALENE & SPOKANE	1917-1940	electric trolley route
Moscow Branch:
SPOKANE & MOSCOW	1911-1939	electric trolley route
route preceded by SPOKANE & COLFAX

Route on the Spokane International Short Line

RPO	Dates	Comments
EASTPORT & SPOKANE	1907-1954

Route on the Washington Idaho & Montana Short Line

RPO	Dates	Comments
BOVILL & PALOUSE	1908-1918

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Contributed 2021 Oct 05 by Mark Metkin

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