It's about as long as The Rhine.
(a.k.a. Rhein, a.k.a. Rijn, a.k.a. Rhin, a.k.a. Rain, a.k.a. Reno, a.k.a. Rhenus, a.k.a. Ryn) (from near Reichenau, Switzerland through Hoek van Holland, Rotterdam, Netherlands)
It's about three-fifths as long as The Colorado River.
In other words, 820 miles is 0.566 times the length of The Colorado River, and the length of The Colorado River is 1.77 times that amount.(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)
It's about half as long as The Danube.
In other words, 820 miles is 0.463 times the length of The Danube, and the length of The Danube is 2.16 times that amount.(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)
It's about two-fifths as long as The Oregon Trail.
In other words, 820 miles is 0.378 times the length of The Oregon Trail, and the length of The Oregon Trail is 2.65 times that amount.(from Independence, Missouri to Oregon City, Oregon)
It's about two-fifths as long as The Volga.
In other words, 820 miles is 0.374 times the length of The Volga, and the length of The Volga is 2.67 times that amount.(a.k.a. Волга, a.k.a. İdel (Идел), a.k.a. Атăл (Atăl), a.k.a. Edil, a.k.a. İdil, a.k.a. Рав (Rav)) (from the Valdai Hills, Tver Oblast, Russia through the Caspian Sea)
The largest river in Europe, the Volga river runs 2,190 miles in total length. World War II's Battle of Stalingrad between the Nazi Germany and the Soviet Union, which resulted in nearly two million casualties, was fought in part for control of the river.
It's about one-third as long as The Mississippi River.
In other words, 820 miles is 0.3504 times the length of The Mississippi River, and the length of The Mississippi River is 2.854 times that amount.(from Lake Itasca, Minnesota through Pilottown, Plaquemines Parish, Louisiana)
It's about three times as long as The Grand Canyon.
In other words, 820 miles is 2.96 times the length of The Grand Canyon, and the length of The Grand Canyon is 0.338 times that amount.(a.k.a. Gran Cañón) (Arizona) (Colorado River miles measure)