Question: How long is the river that Fort Cass was located on?
Context: Cass Lake is a glacially-formed lake in north central Minnesota in the United States.  It is approximately 10 mi long and 7 mi wide, located in Cass and Beltrami counties, within the Chippewa National Forest and the Leech Lake Indian Reservation, adjacent to its namesake city of Cass Lake.  In the Ojibwe language, it is called "Gaa-miskwaawaakokaag" (where there are many red cedar), and was known to early explorers and traders in French as "Lac du Cedre Rouge", and English as "Red Cedar Lake".  It is the 11th largest lake in Minnesota, and the 8th largest lake lying entirely within the borders of the state. Osgood was a city in Cass County, North Dakota in the United States.  The city was located on the east side of the Sheyenne River, three miles south of West Fargo.  Osgood was founded in 1884 as "Garfield" (named in honor of the recently assassinated President James A. Garfield).  The name was changed to "Osgood", in honor of the landowner who ceded the site to C.C. Furnberg, who located a country store and post office at the town site.  The post office and country store ceased operations in 1953.  Furnberg's son, Oscar, donated the store to the Cass County Historical Society, where it was restored and put on display at the Bonanzaville, USA pioneer village museum.  Today, Osgood is no longer a city.  Instead, the general vicinity of Osgood is now an affluent neighborhood of Fargo, North Dakota, centered on a golf course.  The course and neighborhood still bear the "Osgood" name.  Many roads in the neighborhood, such as Fernberg Place and Houkum Court, were named after families who originally lived in the town.  Pictures of the former town can be found in the Osgood Golf Course clubhouse and in the Osgood Hornbacher's supermarket. Fort/Cass station is a Detroit People Mover station in Downtown Detroit, Michigan.  It is located at the intersection of Fort Street and Cass Avenue.  It serves nearby media sources, including newspaper publishers "Detroit Free Press", "Detroit News" and television station WDIV-TV channel 4. Chippewa National Forest is a National Forest located in northcentral Minnesota, United States, in the counties of Itasca, Cass and Beltrami.  Forest headquarters are located in Cass Lake, Minnesota.  There are local ranger district offices in Blackduck, Deer River and Walker. The Hiwassee River has its headwaters on the north slope of Rocky Mountain in Towns County in northern Georgia and flows northward into North Carolina before turning westward into Tennessee, flowing into the Tennessee River a few miles west of State Route 58 in Meigs County, Tennessee.  The river is 147 mi long. Fort Washington Plaza is located at the corner of West Fort Street and Washington Boulevard in downtown Detroit, Michigan.  It occupies the entire block bordered by West Fort Street, Washington Boulevard, Cass Avenue, and West Congress Street.  The high-rise office building stands 16 stories in height.  It was built in 1969, and includes a parking garage.  It was designed in the international architectural style.  It uses mainly concrete and glass. Fort Ellis was a British fort or blockhouse built during the French and Indian War and located at the junction of the Shubenacadie and Stewiacke Rivers, close to Stewiacke, Nova Scotia, Canada.  (The location was labelled Ville Pierre Hebert by Charles Morris.  The 14 Acadian families in the area vacated with the Acadian Exodus.)  Charles Morris recommended a Fort on the Shubenacadie River in 1753.  Governor Lawrence first considered the fort in 1754 as a means to protect Halifax from Mi'kmaq raids.  Lawrence decided the fort would not be effective until after the Battle of Fort Beauséjour.  The fort was completed on October 18, 1761, shortly after the burying of the hatchet ceremony.  The fort was to guard the new road built to connect Truro and Halifax against Mi'kmaq raids.  The fort was called Fort Ellis after Governor Henry Ellis, who was appointed governor weeks after the forts completion.  The fort was never garrisoned and eventually abandoned in 1767.  (Fort Belcher, named after Governor Jonathan Belcher, was built on Salmon River in Lower Onslow, Nova Scotia (1761-67).  Fort Franklin was built at Tatamagouche in 1768, named after Michael Francklin and lasted only a year. ) Fort Cass, established in 1835, was an important site during the Cherokee removal known as the Trail of Tears.  Located on the Hiwassee River in present-day Charleston, Tennessee, it housed a garrison of United States troops and watched over the largest concentration of internment camps where Cherokee were kept during the summer of 1838 before starting the main trek west to Indian Territory.  The camps stretched for many miles through the valley south of Fort Cass toward present-day Cleveland, Tennessee. The Land O'Lakes State Forest is a state forest located primarily in Cass, Minnesota, with portions extending into adjacent Aitkin and Crow Wing counties.  The forest has small shared borders with the Chippewa National Forest to the north, and the Hill River State Forest to east.  Over half of the forest's land is managed by the Minnesota Department of Natural Resources; the remaining land is managed by Cass County or is privately held. Cass Street is a station on the River Line light rail system, located on Cass Street at Route 129 in Trenton, New Jersey.  It is very nearly directly across Route 129 from Trenton State Prison.  Arm & Hammer Park is located five blocks away down Cass Street, while both the Hamilton Avenue stop and Sun National Bank Center are located a few blocks north on Route 129.
Answer: 147 mi