Question: How long is the river that begins 40 mi southwest of the county seat of Beltrami County?

full_context: Document 1: Two Rivers (Red River of the North): The Two Rivers is a 7.0 mi river in Kittson County, northwestern Minnesota, in the United States. Formed by the North Branch of the Two Rivers and the South Branch of the Two Rivers, it is a tributary of the Red River of the North, with its outflow traveling north through Lake Winnipeg and the Nelson River to Hudson Bay.
Document 2: Otter Tail River: The Otter Tail River is a 192 mi river in the west-central portion of the U.S. state of Minnesota. It begins in Clearwater County, 40 mi southwest of Bemidji. It then flows through a number of lakes and cities in Minnesota, including Elbow Lake, Many Point Lake, Chippewa Lake, Height of Land Lake, Frazee, the Pine lakes, Rush Lake, Otter Tail Lake and Ottertail, West Lost Lake, Fergus Falls, and Orwell Lake.
Document 3: Grand Forks, North Dakota: Grand Forks is the third-largest city in the State of North Dakota (after Fargo and Bismarck) and is the county seat of Grand Forks County. According to the 2010 census, the city's population was 52,838, while the total of the city and surrounding metropolitan area was 98,461. Grand Forks, along with its twin city of East Grand Forks, Minnesota, forms the center of the "Grand Forks, ND-MN Metropolitan Statistical Area," which is often called "Greater Grand Forks" or "The Grand Cities".
Document 4: Bemidji, Minnesota: Bemidji ( ) is a city in Beltrami County (and county seat), in north west Minnesota, United States. With a population of 14,301 as of July 1, 2016., it is the largest commercial center between Grand Forks, North Dakota and Duluth, Minnesota. Bemidji houses many Native American services, which includes the Indian Health Service. The city is the central hub of the Red Lake Indian Reservation, White Earth Indian Reservation and the Leech Lake Indian Reservation. Bemidji lies on the south west shore of Lake Bemidji, the northernmost lake feeding the Mississippi River and as such is deemed "The First City On The Mississippi." Bemidji is also called the "curling capital" of the U.S.
Document 5: Duluth, Minnesota: Duluth is a major port city in the U.S. state of Minnesota and the county seat of Saint Louis County. Duluth has a population of 86,110 and is the second-largest city on Lake Superior's shores, after Thunder Bay, Ontario, in Canada; it has the largest metropolitan area on the lake. The Duluth MSA had a population of 279,771 in 2010, the second-largest in Minnesota.
Document 6: South Fork Clearwater River: The South Fork Clearwater River is a 62 mi long river in north-central Idaho in the United States. Draining about 1175 mi2 , the South Fork joins with the Middle Fork Clearwater River to form the Clearwater River, a major tributary of the Snake River.
Document 7: West Swan River: The West Swan River is a 42.2 mi tributary of the East Swan River of Minnesota, flowing to the Saint Louis River and eventually Lake Superior. The West Swan River flows into and out of Snowshoe Lake and Kelly Lake west of Hibbing. Presently there are problems with flowage, due to obstructions in the river. The mines that have polluted the river have left it facing severe problems.
Document 8: Brainerd, Minnesota: Brainerd is a city in Crow Wing County, Minnesota, United States. Its population was 13,592 as of the 2010 census. It is the county seat of Crow Wing County, and is one of the largest cities in Central Minnesota. Brainerd straddles the Mississippi River several miles upstream from its confluence with the Crow Wing River, having been founded as a site for a railroad crossing above said confluence. Brainerd is the principal city of the Brainerd Micropolitan Area, a micropolitan area covering Cass and Crow Wing counties and with a combined population of 91,067 as of the 2010 census. The Brainerd area serves as a major tourist destination for Minnesota, and Baxter is a regional retail center.
Document 9: Embarrass River (Minnesota): The Embarrass River is a 50.5 mi tributary of the Saint Louis River in northern Minnesota, United States. It rises just west of the city of Babbitt and flows southwest, turning briefly south to thread a gap between the Embarrass Mountains to the east and the Mesabi Range to the west. The river flows into the Saint Louis River southeast of Eveleth. During the fur-trading days and the era of exploration, the river was part of a historic trade route from Lower Canada via Lake Superior, across the Height of Land, and down the Rainy River to Lake Winnipeg to the "pays d'en haut"—the fur-bearing regions of the Canadian northwest.
Document 10: Midway River: The Midway River is an 18.8 mi river located in southern Saint Louis County and northeast Carlton County, Minnesota, United States. It is a tributary of the Saint Louis River and flows northeast to southwest. The Midway River rises in the central part of Hermantown, then flows through Midway Township and Thomson Township, before flowing into the Saint Louis River southeast of Cloquet.
Document 11: Greater Grand Forks: "Greater Grand Forks" (officially the Grand Forks, ND-MN Metropolitan Statistical Area) is the name used by some people to designate the twin cities of Grand Forks, North Dakota and East Grand Forks, Minnesota, together with their surrounding areas. The two cities lie directly across from each other on both sides of the Red River of the North, but Grand Forks, with a population of 52,838, is more than five times larger than East Grand Forks, with a population of 8,601. The metropolitan area includes all of the related two counties in the two states: Grand Forks County in North Dakota and Polk County in Minnesota. As of the 2010 census, the MSA had a population of 98,461, and in 2014 estimates placed the total population at 101,842.
Document 12: Beltrami County, Minnesota: Beltrami County ( ) is a county located in the northern part of the U.S. state of Minnesota. As of the 2010 census, the population was 44,442. Its county seat is Bemidji. The county's name comes from the Italian count Giacomo Beltrami, who supposedly explored the area in 1825. The county was created in 1866 and organized in 1896.
Document 13: Bloomington, Minnesota: Bloomington is the fourth largest city in the U.S. state of Minnesota. It is located in Hennepin County on the north bank of the Minnesota River, above its confluence with the Mississippi River. Bloomington lies 10 mi south of downtown Minneapolis. As of the 2010 census the city's population was 82,893, and in 2016 the estimated population was 85,319.
Document 14: Middle Fork Clearwater River: The Middle Fork Clearwater River is a short, but high volume river in northern Idaho and is the major source of the Clearwater River, a tributary of the Snake River. The Middle Fork flows west for 23 mi from the confluence of the Selway River and Lochsa River at Lowell, to the town of Kooskia where it joins with the South Fork Clearwater River to create the Clearwater River. The Middle Fork's entire length is within Idaho County, although a small portion of its watershed extends into Clearwater County.
Document 15: Mankato, Minnesota: Mankato ( ) is a city in Blue Earth, Nicollet, and Le Sueur counties in the state of Minnesota. It is the 22nd biggest city in Minnesota. The population was 41,044 according to 2015 US census estimates, making it the fifth largest city in Minnesota outside of the Minneapolis–Saint Paul metropolitan area. The county seat of Blue Earth County, it is located along a large bend of the Minnesota River at its confluence with the Blue Earth River. Mankato is across the Minnesota River from North Mankato. Mankato and North Mankato have a combined population of over 53,000, according to the 2010 census. It completely encompasses the town of Skyline. North of Mankato Regional Airport, a tiny non-contiguous part of the city is located within Le Sueur County. Most of the city of Mankato is located within Blue Earth County.
ground_truth: 192 mi