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

Context articles: Otter Tail River
KPMI
Battle River (Minnesota)
Giacomo Beltrami
Antelope Valley (southwest Millard County, Utah)
Bloomsburg, Pennsylvania
Fairfield, California
Beltrami County, Minnesota
Great Divide Basin
Bemidji, Minnesota

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.
KPMI (1300 AM, "AM1300 The Legends") is an American radio station licensed to serve the community of Bemidji, the county seat of Beltrami County, Minnesota.
 Two previous formats were all news and all sports.
 It currently broadcasts a classic country radio format.
 The station's broadcast license is held by Paskvan Media, Inc.
 Special programming on the station include "Home Country" hosted by Slim Randles and Pure American Country Radio hosted by Bill Cody (both syndicated by Syndication Networks) "Into The Blue," a Bluegrass Music program hosted by Terry Herd (syndicated by the Bluegrass Radio Network), "Rick Jackson's Country Classics" syndicated by United Stations Radio Networks, "Old Fashioned Revival Hour" and "Riders Radio Theater" rebroadcasts, Bill Gaither's Homecoming Radio, and 2 hours of Gospel music with a mix of Country Gospel, Bluegrass Gospel, Southern Gospel, Jesus Music and Contemporary Christian Music.
The Battle River is a 2.7 mi tributary of Red Lake in Minnesota, the United States.
 It is formed by the junction of its North and South branches.
 The North Branch flows east to west for 13.7 mi entirely in Beltrami County, and the South Branch flows 40.1 mi , starting at the outlet of Bartlett Lake in Koochiching County and flowing west-northwest into Beltrami County.
Giacomo Costantino Beltrami (1779 in Bergamo – January 6, 1855 in Filottrano) was an Italian jurist, author, and explorer, best known for claiming to have discovered the headwaters of the Mississippi River in 1823 while on a trip through much of the United States (later expeditions determined a different source, however).
 Beltrami County in Minnesota is named for him.
 He had an extensive network of notable figures for friends and acquaintances, such as members of the powerful Medici family.
The Antelope Valley of southwest Millard County, Utah is a small 25 mi long valley, adjacent the Ferguson Desert and 40 mi southwest of Sevier Lake.
 The valley is just east of the Nevada border, with Snake Valley and the Burbank Hills.
 The other Antelope Valley of Utah occurs 165 mi east in the Great Basin, in southeast Emery County and extending into adjacent Wayne County.
Bloomsburg is a town in Columbia County, Pennsylvania, United States, located 40 mi southwest of Wilkes-Barre along the Susquehanna River.
 It is the county seat of Columbia County and the only incorporated town in Pennsylvania.
 As of the 2010 census, Bloomsburg had a population of 14,855, with an estimated population of 14,519 in 2013.
Fairfield is a city in, and the county seat of, Solano County, California, in the North Bay sub-region of the San Francisco Bay Area.
 It is generally considered the midpoint between the cities of San Francisco and Sacramento, approximately 40 mi from the city center of both cities, approximately 40 mi from the city center of Oakland, less than 19 mi from Napa Valley, 16 mi from the Carquinez Bridge, and 14 mi from the Benicia Bridge.
 Fairfield was founded in 1856 by clippership captain Robert H. Waterman, and named after his former hometown of Fairfield, Connecticut.
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.
The Great Divide Basin or Great Divide Closed Basin is an area of land in Wyoming's Red Desert (United States) where none of the water falling as rain to the ground drains into any ocean, directly or indirectly.
 It is therefore considered an endorheic basin, and it adjoins the Continental Divide in southern Wyoming.
 To the west of the basin is the Green River watershed, draining to the Gulf of California/Pacific Ocean; to the east is the North Platte watershed, draining to the Gulf of Mexico/Atlantic Ocean.
 The basin is very roughly rectangular in shape; the northwest corner is in the Wind River Range near South Pass, about 40 mi southwest of Lander, and the southeast corner is in the Sierra Madre Range near Bridger Pass, about 20 mi southwest of Rawlins.
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.