Armando Bernal, age 9' of Tucson, Arizona, for his question:

Which is the longest river in the United States?

It starts taut as a bright little stream in southwestern Montana and flows 3.,872 miles to meet the sea at the Gulf of Mexico . On the tray it gathers up countless streams and several hundred tributaries and it , changes its name four times. The baby river is hatched near the continental divide, not far from where Red Rock Pass cuts a cleft in the lofty Rockies.  For a few miles as it courses northward down the mountain slopes it is called the Red Rock river Soon it becomes the Beaverhead river and then the Jefferson. At Three Forks Montana the Jefferson gathers in its first two sizeable tributaries, the Gallatin and the Madison. It also takes a new name the Missouri.

The young river is clean and clear as it wanders northward. Near Helena, it cuts its way through a steep walled canyon and at Great Falls it somersaults through a series of waterfalls. But this playfulness stops when it reaches the greet reservoir at Fort Peck. It widens and proceeds sedately into North Dakota. Almost at once it is joined by the Yellowstone river, loaded with silt and dirt from the dusty prairies. Countless other streams add their muddy waters to the growing Missouri and from here the great river can justly be called the Big Muddy,

As it grows , the Missouri plays a part in the geography of the land. It draws a wide brown crayon mark along certain state borders. It marks off parts of the boundaries between South Dakota and Nebraska, between Nebraska and Iowa, between Nebraska and Missouri and between Missouri. and Kansas.  At Kansas City it welcomes the Kansas river and goes on its way to rendezvous with the biggest of all its tributaries,

This huge tributary sprang from a clear lake in Minnesota,‑ far, far from Iced Rock Pass, It, too, gathered countless streams and the Indians called it Mississippi, Father of Waters. When it meets the muddy Missouri just north of St. Louis it is a wide and mighty river of clear water, The Missouri now changes its name for the last time and becomes the Mississippi. It has already traveled 2340 miles to reach this point, more than twice as far as has the Mississippi. Geographically, this means that the Mississippi is really a tributary of the Missouri, though we did not know this when the great rivers were first discovered and named,

The Ohio the Tennessee, the Osage, the Arkansas, the Red River and countless others add their waters to the swelling torrent on its way to New Orleans. Altogether, the vast river system drains all or part of 31 states and two Canadian Provinces an area of one and a quarter million square miles, equal to half of Europe,