It's about one-fifteenth as long as The Colorado River.
In other words, the length of The Colorado River is 14.2 times 813 furlongs.(a.k.a. Aha Kwahwat, a.k.a. Grand River, a.k.a. Tizon River, a.k.a. Tecon River, a.k.a. Tison River) (from Grand Lake, Colorado through the Gulf of California)
The Colorado River runs 11,600 furlongs in length. Along this length, the river descends from its source, approximately 13.7 furlongs above sea level in the Rocky Mountains, to its mouth in the Gulf of California.
It's about fifteen times as tall as Maxwell Montes.
In other words, the height of Maxwell Montes is 0.067 times 813 furlongs.(Ishtar Terra, Venus)
Maxwell Montes rises to a total height of 55 furlongs. Since Venus does not seem to have the kind of tectonic activity which gives rise to mountains on Earth, the origin of the Venusian mountain remains the subject of some dispute.
It's about fifteen times as tall as The Challenger Deep (Marianas Trench).
In other words, 813 furlongs is 15.002 times the height of The Challenger Deep (Marianas Trench), and the height of The Challenger Deep (Marianas Trench) is 0.066658 times that amount.(near Marianas Islands, a.k.a. Ladrones Islands, northwestern Pacific Ocean) (depth below sea level)
The Challenger Deep, at the southern end of the Marianas Trench, reaches a depth of 54.194 furlongs below sea level. There has been only one manned expedition to the bottom of Challenger Deep — a 1960 voyage that took 4 hours and 48 minutes to reach the bottom.
It's about one-fifteenth as long as The Danube.
In other words, the length of The Danube is 17.4 times 813 furlongs.(a.k.a. Donau, a.k.a. Dunaj, a.k.a. Dunav, a.k.a. Duna, a.k.a. Дунав (Dunav), a.k.a. Dunărea, a.k.a. Дунáй (Dunay), a.k.a. Tuna) (from Breg Martinskapelle, Black Forest, Germany through the Danube Delta, Romania)
The Danube river runs 14,200 furlongs in total length. Intersecting Vienna, Austria; Bratislava, Slovakia; Budapest, Hungary; and Belgrade, Serbia, the Danube touches more capital cities than any other river.
It's about eighteen times as tall as a Mauna Loa.
In other words, 813 furlongs is 17.84 times the height of a Mauna Loa, and the height of a Mauna Loa is 0.05605 times that amount.(Hawaii) (Hawaiian island volcano) (total height from seafloor)
Mauna Loa, one of the five volcanoes which forms the island of Hawaii and the tallest mountain in total height in the world, rises to 45.73 furlongs above the seafloor. The peak of Loa is home to the approximately 6,000 sq. m (0.6 ha) Lake Waiau, one of the highest altitude lakes in the United States outside of Colorado.
It's about eighteen-and-a-half times as tall as Mount Everest.
In other words, the height of Mount Everest is 0.0541 times 813 furlongs.(a.k.a. Mount Chomolungma, a.k.a. सगरमाथा, a.k.a. Chajamlungma, a.k.a. ཇོ་མོ་གླང་མ, a.k.a. 珠穆朗玛峰, a.k.a. Zhūmùlǎngmǎ Fēng) (Sagarmatha Zone, Nepal and Tibet, China) (to summit, excluding snow depth)
Mount Everest is 44 furlongs above sea level at its summit. The plate tectonics of the Indian subcontinent continuously alter the mountain's peak — raising it by 0.0000199 furlongs and shifting it to the northeast by 0.0000224 furlongs each year.
It's about one-twentieth as long as The Oregon Trail.
In other words, 813 furlongs is 0.0469 times the length of The Oregon Trail, and the length of The Oregon Trail is 21.3 times that amount.(from Independence, Missouri to Oregon City, Oregon)
The historic Oregon Trail stretched 17,300 furlongs across five (sometimes six) states in the western United States. In the early years of the Trail's existence, the trip was estimated to have taken an average of 160 days.