Question: The Boulder Mountains are a mountain range running north–south west of Boulder between Helena and Butte in the U.S. state of Montana, parts of the range are in four different counties, including Deer Lodge County is a county in the U.S. state of Montana, and was founded in what year?

Context paragraphs:
Boulder Mountains (Montana): The Boulder Mountains are a mountain range running north–south west of Boulder between Helena and Butte in the U.S. state of Montana.  Parts of the range are in four different counties: Deer Lodge, Jefferson, Lewis and Clark, and Silver Bow.

Deer Lodge Pass: Deer Lodge Pass, elevation 5879 ft , is a mountain pass on the Continental Divide in southwestern Montana, about 11 miles southwest of Butte.  It is traversed by Interstate 15 and is one of three crossings of the Divide by I-15 (all in Montana), the others being Monida Pass (on the border with Idaho) and Elk Park Pass north of Butte.  Unlike most other passes in western Montana, Deer Lodge Pass is in the midst of treeless, rolling hills (reminiscent of Interstate 80 in Wyoming), and the grades on the highway are relatively gentle.

Anaconda Range: The Anaconda Range, informally known as the "Pintlers", is a group of high mountains located in southwestern Montana, in the northwestern United States.  The mountain range takes its name from the nearby town of Anaconda, founded by Marcus Daly in 1883.  It runs northeast approximately 50 miles (80 km) from Lost Trail Pass to a point near the community of Anaconda, covering parts of Ravalli, Deer Lodge, Granite and Beaverhead Counties.  To the northwest are the Sapphire Mountains, to the south is the Big Hole Valley.  Due north, the range blends into the Flint Creek Range, and to the southeast lies the Big Hole River and Pioneer Mountains.  The crest of the range is part of the Continental Divide, rising to 10,793 feet (3290 m) at West Goat Peak.  Other major summits include Mt. Evans (10,641 ft, 3243 m), Mt. Haggin (10,607 ft, 3233 m), Warren Peak (10,463 ft, 3189 m), and East Goat Peak (10,399 ft, 3170 m).  West Pintler Peak, located in a more commonly visited area, rises to 9894 feet (2895 m).  Much of the range is protected in the Anaconda-Pintler Wilderness Area.

Deer Lodge County, Montana: Deer Lodge County is a county in the U.S. state of Montana.  As of the 2010 census, the population was 9,298.  It forms a consolidated city-county government with its county seat of Anaconda.  The county was founded in 1865.

Bowman Field (Montana): Bowman Field (FAA LID: 3U3) is a public airport located three miles (5 km) northeast of the central business district of Anaconda, a city in Deer Lodge County, Montana, United States.  It is owned by Anaconda City and Deer Lodge County.

Clark Fork River: The Clark Fork, or the Clark Fork of the Columbia River, is a river in the U.S. states of Montana and Idaho, approximately 310 mi long.  The largest river by volume in Montana, it drains an extensive region of the Rocky Mountains in western Montana and northern Idaho in the watershed of the Columbia River.  The river flows northwest through a long valley at the base of the Cabinet Mountains and empties into Lake Pend Oreille in the Idaho Panhandle.  The Pend Oreille River in Idaho, Washington, and British Columbia, Canada which drains the lake to the Columbia in Washington, is sometimes included as part of the Clark Fork, giving it a total length of 479 mi , with a drainage area of 25820 sqmi .  In its upper 20 mi in Montana near Butte, it is known as Silver Bow Creek.  Interstate 90 follows much of the upper course of the river from Butte to northwest of Missoula.  The highest point within the river's watershed is Mount Evans at 10641 ft in Deer Lodge County, Montana along the Continental Divide.

Dry Cottonwood Creek (Deer Lodge County, Montana): Dry Cottonwood Creek is a creek in Deer Lodge County, Montana.  Approximately 10 mi long, it flows northwest out of the southern reaches of the Boulder Mountains into the Clark Fork river near Deer Lodge, Montana.  Sapphires are found along this creek.

Meyers Fire: The Meyers Fire is in Beaverhead-Deerlodge National Forest and Bitterroot National Forest in the U.S. state of Montana and was first reported on July 17, 2017 at 5:21pm.  Located approximately 25 mi southwest of Phillipsburg, Montana, the Meyers Fire is a natural fire that was caused by lightning.  As of September 28, 2017, it encompassed 62034 acres .  The Meyers Fire originated after a lightning storm passed over the region, starting a fire in remote terrain in Granite County, Montana within Beaverhead-Deerlodge National Forest.  The fire then burned into neighboring Ravalli County, Montana and then crossed the continental divide into Beaverhead County, Montana and Deer Lodge County, Montana, where it entered Bitterroot National Forest.  By August 3, the Meyers and Whetstone Fires merged, with the name of the former being the official name of the event.  Due to a heavy fuel load, exceptionally dry conditions with high heat and periods of strong winds, the Meyers Fire had periods of explosive growth during August and early September, leading to evacuations of nearby communities.

Warm Springs, Montana: Warm Springs is an unincorporated community in Deer Lodge County, Montana, United States, operated by the state of Montana.  It is the site of Montana State Hospital, the only long term psychiatric hospital operated by the state of Montana.  The hospital was founded by the Territorial Government of Montana in 1877.  The "warm springs" are located on the hospital campus.  Hot water seeps from a limestone cone that is about 40 feet high.  The Native Americans called this the "Lodge of the Whitetailed Deer" giving the Deer Lodge Valley its name.  There are no community services other than a bar and convenience store on the frontage road and a post office (zip code 59756) on the hospital campus.  Brown trout fishing can be found in the Clark Fork River just east of Warm Springs and in the ponds on the Warm Springs Wildlife Management Area.

List of counties in Montana: This is a list of the 56 counties in the U.S. state of Montana.  Montana has two consolidated city-counties—Anaconda with Deer Lodge County and Butte with Silver Bow County.  The portion of Yellowstone National Park that lies within Montana was not part of any county until 1978, when part of it was nominally added to Gallatin County, and the rest of it to Park County.  Eight counties of the state are composed of two or more words.

Supporting paragraphs: Boulder Mountains (Montana) Deer Lodge County, Montana
Answer: 1865