Question: Which county in Montana is the largest by area in the state which includes the unincorporated community of Monida? 

Context paragraphs:
Rubidoux, California: Rubidoux ( ) was a census-designated place and an unincorporated community in Riverside County, California.  As of the 2010 census, the population was 34,280, up from 29,180 at the 2000 census.  Like much of the fast-growing Inland Empire Metropolitan Area, Rubidoux is rapidly changing from a rural area of quarries and dairy farms to an exurb of Riverside.  As of the 2000 Census, Rubidoux was the largest unincorporated community in the Inland Empire and in Riverside County.  On July 1, 2011, the CDP became part of the newly incorporated City of Jurupa Valley.

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.

Summer Shade, Kentucky: Summer Shade is a small unincorporated community and census-designated place (CDP) in Metcalfe County, Kentucky, United States.  Originally the area was known as Sartain Precinct and later as Glover's Creek; W.M. Riggs, the postmaster, changed the name to Summer Shade in 1872.  The rural-dominated area is home to the Kingsford Charcoal factory.  This plant is the largest briquette factory in the world.  The community is part of the Glasgow Micropolitan Statistical Area.  State highway 90, connecting Glasgow to the Dale Hollow Lake area, runs through Summer Shade.  There is one school in Summer Shade, the Summer Shade Elementary School that goes from grades K-6.  Students in 7th and 8th grade public school attend the Metcalfe County Middle School in Edmonton.  Students in 9th-12th grade public school attend the Metcalfe County High School in Edmonton.  One of the foremost doctors in south-central Kentucky and the state during the twentieth century was Dr. C.C. Howard, who was born in Summer Shade.  He worked to establish tuberculosis hospitals throughout Kentucky and to improve medical care in the rural areas of the state.

Seabrook, New Jersey: Seabrook is an unincorporated community located within Upper Deerfield Township in Cumberland County, New Jersey, United States.  The area is served as United States Postal Service ZIP code 08302.  The unincorporated community and the census-designated Place Seabrook Farms within it are each named after Charles F. Seabrook, a businessman who at one point ran the largest irrigated truck farm in the world in this region.

Sawyerville, Alabama: Sawyerville, previously known as Sawyers Depot, is an unincorporated community in west-central Hale County, Alabama and is a part of the Tuscaloosa metropolitan area.  It derives its name from the town’s first post master.  The community is rural and came to flourish due to its proximity to the railroad that once traveled through it.  The community covers the historic area of the county once called Hollow Square and includes the abandoned town site of Erie, the former county seat of Greene County.  It also includes the communities of Wedgeworth, Melton, Warrior Dam, and Mason Bend.  The area was the site of several Pickens family plantations, most notably those of early Alabama governor, Israel Pickens, and his younger brother, Samuel Pickens.  The Samuel Pickens homestead, Umbria Plantation, was destroyed by fire in 1971.

Beaverhead County, Montana: Beaverhead County is the largest county by area in the U.S. state of Montana.  As of the 2010 census, the population was 9,246.  Its county seat is Dillon.  The county was founded in 1865.

Washington Dulles International Airport: Washington Dulles International Airport (IATA: IAD, ICAO: KIAD, FAA LID: IAD) is an international airport in Loudoun and Fairfax counties in Virginia, United States, 26 miles (42 km) west of downtown Washington, D.C. The airport serves the Baltimore–Washington metropolitan area, centered on the District of Columbia.  The airport is named after John Foster Dulles, the 52nd Secretary of State who served under President Dwight D. Eisenhower.  The Dulles main terminal is a well-known landmark designed by Eero Saarinen.  Operated by the Metropolitan Washington Airports Authority, Dulles Airport occupies 13,000 acres (52.6 km) straddling the Loudoun-Fairfax line.  Most of the airport is in the unincorporated community of Dulles, in Loudoun County, with a small portion in the unincorporated community of Chantilly in Fairfax County.

State Hill, Pennsylvania: State Hill is a rather large and sparsely populated unincorporated community in Lower Heidelberg Township, Pennsylvania, in Berks County.  The area that is now State Hill was once called Lorah, Pennsylvania.  This was named for the first settler within the village's boundary.  At one time, the main road through the unincorporated community was called Dry Road.  It received the name for lack of water to tap into for wells.  This road is now known as Brownsville Road.  The village started out as just a few cabins, but by the mid-1800s had built a Tavern.  It was called Dry Tavern, named after the road it was on.  The village has a great view of Blue Marsh Lake along Brownsville Rd.  It is also home to an extinct elementary school, Lower Heidelberg Consolidated School, which ran from 1931 to 2006.  It is served by the academically prestigious Wilson School District.  State Hill also has several businesses, including Berks Western Telecom, Ganly's Pub and Deli, Blue Marsh Taxidermy, a Fire Station, and a Police station.  Ganly's was built in 1993.  It was built where The Beer Garden Tavern used to be on.  There are also 5-6 row homes on the intersection of State Hill Road and Brownsville Road.  These were built by the government for the residents of the now flooded Blue Marsh village.

Monida, Montana: Monida is an unincorporated community in Beaverhead County, Montana, United States.  Monida is located on Interstate 15 at the top of Monida Pass, 14.7 mi east-southeast of Lima.  The community is situated on the Continental Divide at the Idaho state line.  It has a permanent population of two.

Houghton Lake (Michigan): Houghton Lake is a large lake in Roscommon County.  The unincorporated community of Prudenville is at the southeastern end of the lake, while the unincorporated communities of Houghton Lake and Houghton Lake Heights are on the southwest and west shores.  It is the largest inland lake in the state of Michigan, and one of the largest "natural" inland lakes in the United States (many man-made impoundments are much larger).  The lake is approximately 7+1/2 mi north to south, and about 4+1/2 mi at it widest point.  Houghton Lake has c. 30 mi of total shoreline and its waters cover 20044 acre .  It is an extremely popular resort and fishing area year round.  Houghton Lake is the site of Tip-Up-Town USA, a large ice fishing and winter sports festival with several events on the frozen waters of the lake itself.  Houghton Lake is named after the first state geologist, Douglass Houghton who explored the area.  Houghton County, in the Upper Peninsula of Michigan is also named after Douglass Houghton.  The name of the lake is pronounced by Michigan citizens as "HOTE'n".

Supporting paragraphs: Monida, Montana Beaverhead County, Montana
Answer: Beaverhead County