County
| FIPS Code
[1] | County seat
[2] | Established
[2] | Origin
| Etymology
| Population
| Area
| Map
|
| Beaverhead County | 001 | Dillon | 1864 | Original County | Beaverhead County was named after Beaverhead Rock in the Jefferson River, which is shaped like a beaver's head. | &0000000000009202.0000009,202 | &0000000000005543.0000005,543 sq mi
(&0000000000014356.00000014,356 km2) |  |
| Big Horn County | 003 | Hardin | 1913 | Rosebud County, Yellowstone County | Bighorn County was named for Bighorn sheep in the area. | &0000000000012671.00000012,671 | &0000000000004995.0000004,995 sq mi
(&0000000000012937.00000012,937 km2) |  |
| Blaine County | 005 | Chinook | 1895 | Chouteau County | Blaine County was named after James G. Blaine, United States Secretary of State and presidential candidate. | &0000000000007009.0000007,009 | &0000000000004226.0000004,226 sq mi
(&0000000000010945.00000010,945 km2) |  |
| Broadwater County | 007 | Townsend | 1897 | Jefferson County, Meagher County | Broadwater County was named after Charles A. Broadwater, a pioneer in the area and colonel in the United States Army. | &0000000000004385.0000004,385 | &0000000000001192.0000001,192 sq mi
(&0000000000003087.0000003,087 km2) |  |
| Carbon County | 009 | Red Lodge | 1895 | Park County, Yellowstone County | Carbon County was named for Coal deposits in the area. | &0000000000009552.0000009,552 | &0000000000002048.0000002,048 sq mi
(&0000000000005304.0000005,304 km2) |  |
| Carter County | 011 | Ekalaka | 1917 | Fallon County | Carter County was named after Thomas Henry Carter,a U.S. Senator from Montana. | &0000000000001360.0000001,360 | &0000000000003340.0000003,340 sq mi
(&0000000000008651.0000008,651 km2) |  |
| Cascade County | 013 | Great Falls | 1887 | Chouteau County, Meagher County | Cascade County was named after the Great Falls of the Missouri River. | &0000000000080357.00000080,357 | &0000000000002698.0000002,698 sq mi
(&0000000000006988.0000006,988 km2) |  |
| Chouteau County | 015 | Fort Benton | 1865 | Original County | Chouteau County was named after Jean Pierre Chouteau and his son Pierre Chouteau, Jr.. They were part of the Chouteau fur-trading family. | &0000000000005970.0000005,970 | &0000000000003973.0000003,973 sq mi
(&0000000000010290.00000010,290 km2) |  |
| Custer County | 017 | Miles City | 1865 | Big Horn County | George Armstrong Custer, United States Army officer | &0000000000011696.00000011,696 | &0000000000003783.0000003,783 sq mi
(&0000000000009798.0000009,798 km2) |  |
| Daniels County | 019 | Scobey | 1920 | Sheridan County, Valley County | Mansfield A. Daniels, an early rancher and storekeeper | &0000000000002017.0000002,017 | &0000000000001426.0000001,426 sq mi
(&0000000000003693.0000003,693 km2) |  |
| Dawson County | 021 | Glendive | 1865 | Unorganized lands | Andrew Dawson, a trapping official and major in the United States Army | &0000000000009059.0000009,059 | &0000000000002373.0000002,373 sq mi
(&0000000000006146.0000006,146 km2) |  |
| Deer Lodge County | 023 | Anaconda | 1864 | Original County | Deer Lodge Valley, which in turn was either named for the Native American name "Lodge of the White-tailed Deer" or a salt lick where deer came in droves | &0000000000009417.0000009,417 | &0000000000000737.000000737 sq mi
(&0000000000001909.0000001,909 km2) |  |
| Fallon County | 025 | Baker | 1913 | Custer County | Benjamin O'Fallon, a Federal Native American agent | &0000000000002837.0000002,837 | &0000000000001620.0000001,620 sq mi
(&0000000000004196.0000004,196 km2) |  |
| Fergus County | 027 | Lewistown | 1885 | Original County | The father of Andrew Fergus, one of the first settlers | &0000000000011893.00000011,893 | &0000000000004339.0000004,339 sq mi
(&0000000000011238.00000011,238 km2) |  |
| Flathead County | 029 | Kalispell | 1893 | Missoula County | Flathead Native Americans | &0000000000074471.00000074,471 | &0000000000005099.0000005,099 sq mi
(&0000000000013206.00000013,206 km2) |  |
| Gallatin County | 031 | Bozeman | 1864 | Original County | Albert Gallatin, the United States Secretary of the Treasury at the time of the Lewis and Clark Expedition | &0000000000067831.00000067,831 | &0000000000002507.0000002,507 sq mi
(&0000000000006493.0000006,493 km2) |  |
| Garfield County | 033 | Jordan | 1919 | Dawson County | Probably James A. Garfield, the twentieth President of the United States | &0000000000001279.0000001,279 | &0000000000004668.0000004,668 sq mi
(&0000000000012090.00000012,090 km2) |  |
| Glacier County | 035 | Cut Bank | 1919 | Teton County | Glacier National Park, which borders the county | &0000000000013247.00000013,247 | &0000000000002995.0000002,995 sq mi
(&0000000000007757.0000007,757 km2) |  |
| Golden Valley County | 037 | Ryegate | 1920 | Musselshell County, Sweet Grass County | Probably named in a promotional attempt to lure settlers to the area | &0000000000001042.0000001,042 | &0000000000001175.0000001,175 sq mi
(&0000000000003043.0000003,043 km2) |  |
| Granite County | 039 | Philipsburg | 1893 | Deer Lodge County, Missoula County | Granite Peak, the highest point in Montana which also contained a silver mine named "Granite" | &0000000000002830.0000002,830 | &0000000000001728.0000001,728 sq mi
(&0000000000004475.0000004,475 km2) |  |
| Hill County | 041 | Havre | 1912 | Chouteau County | James J. Hill, a leading railroad tycoon | &0000000000016673.00000016,673 | &0000000000002896.0000002,896 sq mi
(&0000000000007501.0000007,501 km2) |  |
| Jefferson County | 043 | Boulder | 1864 | Original County | Thomas Jefferson, the third President of the United States | &0000000000010049.00000010,049 | &0000000000001657.0000001,657 sq mi
(&0000000000004292.0000004,292 km2) |  |
| Judith Basin County | 045 | Stanford | 1920 | Cascade County, Fergus County | The Judith River which was in turn named by William Clark for Julia "Judith" Hancock, whom he would later marry | &0000000000002329.0000002,329 | &0000000000001870.0000001,870 sq mi
(&0000000000004843.0000004,843 km2) |  |
| Lake County | 047 | Polson | 1923 | Flathead County, Missoula County | Flathead Lake | &0000000000026507.00000026,507 | &0000000000001494.0000001,494 sq mi
(&0000000000003869.0000003,869 km2) |  |
| Lewis and Clark County | 049 | Helena | 1864 | Original County | Meriwether Lewis and William Clark, the famous explorers | &0000000000055716.00000055,716 | &0000000000003461.0000003,461 sq mi
(&0000000000008964.0000008,964 km2) |  |
| Liberty County | 051 | Chester | 1920 | Chouteau County, Hill County | The sentiment of the inhabitants when the county was formed soon after World War I | &0000000000002158.0000002,158 | &0000000000001430.0000001,430 sq mi
(&0000000000003704.0000003,704 km2) |  |
| Lincoln County | 053 | Libby | 1909 | Flathead County | Probably Abraham Lincoln, the 16th President of the United States | &0000000000018837.00000018,837 | &0000000000003613.0000003,613 sq mi
(&0000000000009358.0000009,358 km2) |  |
| McCone County | 055 | Circle | 1919 | Dawson County, Richland County | George McCone, a Montana state senator who helped create the county | &0000000000001977.0000001,977 | &0000000000002643.0000002,643 sq mi
(&0000000000006845.0000006,845 km2) |  |
| Madison County | 057 | Virginia City | 1864 | Original County | James Madison, the fourth President of the United States and the Secretary of State at the time of the Lewis and Clark Expedition | &0000000000006851.0000006,851 | &0000000000003587.0000003,587 sq mi
(&0000000000009290.0000009,290 km2) |  |
| Meagher County | 059 | White Sulphur Springs | 1867 | Chouteau County, Gallatin County | Thomas Francis Meagher, a acting Governor of the Montana Territory | &0000000000001932.0000001,932 | &0000000000002392.0000002,392 sq mi
(&0000000000006195.0000006,195 km2) |  |
| Mineral County | 061 | Superior | 1914 | Missoula County | Many mines and mining prospects within the county | &0000000000003884.0000003,884 | &0000000000001220.0000001,220 sq mi
(&0000000000003160.0000003,160 km2) |  |
| Missoula County | 063 | Missoula | 1864 | Original County | Supposedly a contraction of the Flathead word, "im-i-sul-e-etiku", meaning "by or near the place of fear or ambush", a reference to Hell Gate Canyon, in which Flathead Native Americans were sometimes attacked by Blackfeet | &0000000000095802.00000095,802 | &0000000000002598.0000002,598 sq mi
(&0000000000006729.0000006,729 km2) |  |
| Musselshell County | 065 | Roundup | 1911 | Fergus County, Meagher County, Yellowstone County | The Musselshell River, named in turn by the Lewis and Clark Expedition presumably due to mussels found on its banks | &0000000000004497.0000004,497 | &0000000000001867.0000001,867 sq mi
(&0000000000004836.0000004,836 km2) |  |
| Park County | 067 | Livingston | 1887 | Gallatin County | Nearby Yellowstone National Park | &0000000000015694.00000015,694 | &0000000000002656.0000002,656 sq mi
(&0000000000006879.0000006,879 km2) |  |
| Petroleum County | 069 | Winnett | 1926 | Fergus County | The production of petroleum at Cat Creek | &0000000000000493.000000493 | &0000000000001654.0000001,654 sq mi
(&0000000000004284.0000004,284 km2) |  |
| Phillips County | 071 | Malta | 1915 | Blaine County, Valley County | B.D. Phillips, a leading sheepman, rancher, and pioneer in the county | &0000000000004601.0000004,601 | &0000000000005140.0000005,140 sq mi
(&0000000000013313.00000013,313 km2) |  |
| Pondera County | 073 | Conrad | 1919 | Chouteau County, Teton County | Originally pend d'oreille, French words meaning "ear pendant"; the name was changed to a form resembling the phonetic spelling to avoid confusion with the lake and town of that name in Idaho | &0000000000006424.0000006,424 | &0000000000001625.0000001,625 sq mi
(&0000000000004209.0000004,209 km2) |  |
| Powder River County | 075 | Broadus | 1919 | Custer County | The Powder River, which in turn was named for gunpowder-like sand along its banks | &0000000000001858.0000001,858 | &0000000000003297.0000003,297 sq mi
(&0000000000008539.0000008,539 km2) |  |
| Powell County | 077 | Deer Lodge | 1901 | Deer Lodge County | Mount Powell, which in turn was named for John Wesley Powell, the early environmentalist and explorer | &0000000000007180.0000007,180 | &0000000000002326.0000002,326 sq mi
(&0000000000006024.0000006,024 km2) |  |
| Prairie County | 079 | Terry | 1915 | Dawson County, Fallon County | The county's location on the Great Plains | &0000000000001199.0000001,199 | &0000000000001737.0000001,737 sq mi
(&0000000000004499.0000004,499 km2) |  |
| Ravalli County | 081 | Hamilton | 1893 | Missoula County | Anthony Ravalli, a Jesuit missionary who came to the area in 1845 | &0000000000036070.00000036,070 | &0000000000002394.0000002,394 sq mi
(&0000000000006200.0000006,200 km2) |  |
| Richland County | 083 | Sidney | 1914 | Dawson County | Named in an attempt to lure in settlers | &0000000000009667.0000009,667 | &0000000000002084.0000002,084 sq mi
(&0000000000005398.0000005,398 km2) |  |
| Roosevelt County | 085 | Wolf Point | 1919 | Sheridan County | Theodore Roosevelt, the twenty-sixth President of the United States | &0000000000010620.00000010,620 | &0000000000002356.0000002,356 sq mi
(&0000000000006102.0000006,102 km2) |  |
| Rosebud County | 087 | Forsyth | 1901 | Custer County | The Rosebud River, which was named for the many wild roses along its banks | &0000000000009383.0000009,383 | &0000000000005012.0000005,012 sq mi
(&0000000000012981.00000012,981 km2) |  |
| Sanders County | 089 | Thompson Falls | 1906 | Missoula County | Wilbur Fiske Sanders, a pioneer, vigilante, and U.S. Senator from Montana | &0000000000010227.00000010,227 | &0000000000002762.0000002,762 sq mi
(&0000000000007154.0000007,154 km2) |  |
| Sheridan County | 091 | Plentywood | 1913 | Valley County | Philip Sheridan, Civil War general | &0000000000004105.0000004,105 | &0000000000001677.0000001,677 sq mi
(&0000000000004343.0000004,343 km2) |  |
| Silver Bow County | 093 | Butte | 1881 | Deer Lodge County | Silver Bow Creek. There are multiple theories explaining how the creek got its name | &0000000000034606.00000034,606 | &0000000000000718.000000718 sq mi
(&0000000000001860.0000001,860 km2) |  |
| Stillwater County | 095 | Columbus | 1913 | Carbon County, Sweet Grass County, Yellowstone County | Stillwater River, named for its very slow current | &0000000000008195.0000008,195 | &0000000000001795.0000001,795 sq mi
(&0000000000004649.0000004,649 km2) |  |
| Sweet Grass County | 097 | Big Timber | 1895 | Meagher County, Park County, Yellowstone County | The abundant sweet grass in the county | &0000000000003609.0000003,609 | &0000000000001855.0000001,855 sq mi
(&0000000000004804.0000004,804 km2) |  |
| Teton County | 099 | Choteau | 1893 | Chouteau County | The Teton Range which is in turn named for the French word for beast, teton. | &0000000000006445.0000006,445 | &0000000000002273.0000002,273 sq mi
(&0000000000005887.0000005,887 km2) |  |
| Toole County | 101 | Shelby | 1914 | Hill County, Teton County | Joseph Toole, the first Governor of Montana | &0000000000005267.0000005,267 | &0000000000001911.0000001,911 sq mi
(&0000000000004949.0000004,949 km2) |  |
| Treasure County | 103 | Hysham | 1919 | Rosebud County | Named promotionally to attract new settlers | &0000000000000861.000000861 | &0000000000000979.000000979 sq mi
(&0000000000002536.0000002,536 km2) |  |
| Valley County | 105 | Glasgow | 1893 | Dawson County | Much of the county lies within the valley of the Milk River | &0000000000007675.0000007,675 | &0000000000004921.0000004,921 sq mi
(&0000000000012745.00000012,745 km2) |  |
| Wheatland County | 107 | Harlowton | 1917 | Meagher County, Sweet Grass County | The many wheat fields in the county | &0000000000002259.0000002,259 | &0000000000001423.0000001,423 sq mi
(&0000000000003686.0000003,686 km2) |  |
| Wibaux County | 109 | Wibaux | 1914 | Dawson County, Fallon County, Richland County | Pierre Wibaux, a pioneer and cattleman | &0000000000001068.0000001,068 | &0000000000000889.000000889 sq mi
(&0000000000002302.0000002,302 km2) |  |
| Yellowstone County | 111 | Billings | 1893 | Custer County | The Yellowstone River, named in turn for the yellow rocks found along it | &0000000000129352.000000129,352 | &0000000000002635.0000002,635 sq mi
(&0000000000006825.0000006,825 km2) |  |
