River day

More river graphics.

The Missouri has such an eccentric course. Poor Lewis and Clark, thinking it was just going to flow tidily west into the Pacific and be a super-useful transportation route.

Missouri river basin (Wikimedia Commons)

Missouri river basin (Wikimedia Commons)

West! North! West! North north north north! Westnorthwestnorthwest west west west SOUTH!

And then it breaks into three smaller ones and the Pacific is still way over on the other side of a lot of mountains.

And then look at the comparative volumes. I had NO idea the Ohio was 20 times the size of the other two.


H/t Alex

The Mississippi is really the Ohio. Who knew??


  1. Al Dente says

    The longest river in North America has no name.

    It’s generally considered that the main river is the longest one and tributaries are shorter. The Missouri River is longer than the Upper Mississippi (above St. Louis) so therefore the Upper Mississippi is a tributary of the Missouri-Lower Mississippi Rivers.

  2. Erp says

    And then look further north to the Mackenzie River basin and the Yukon river which bisects Alaska.

  3. chrislawson says

    Did Lewis and Clark really think the Missouri flowed southeast to the Gulf of Mexico and west to the Pacific? That’s a bit weird.

  4. says

    Not southeast, that I recall, but Jefferson and others thought it might (or probably did) flow to the Pacific, yes – because they just didn’t know much about the geography of the Louisiana Purchase. It’s not a daft thing to think in a condition of very incomplete knowledge.

  5. moarscienceplz says

    Interesting. I took a trip to New Orleans a few years ago, and was surprised and a bit disappointed that the Mississippi looked a lot smaller than I expected.. Now I see that more than half the flow is diverted away from NOLA. I guess I’m going to have to go to Natchez to see Mark Twain’s Mississippi.

  6. Trebuchet says

    There actually is a little lake in Yellowstone Park, Isa Lake, that sits smack on the Continental Divide and has two outlets, one to the Gulf via the Yellowstone, Missouri, and Mississippi; and the other to the Pacific via the Snake and Columbia.

  7. says

    I was thinking the same as chrislawson @3. Did they really think it would get them to the Pacific? Certainly they would have understood that water had to flow down from a higher elevation and certainly they would have known the Pacific and Gulf of Mexico would be the same elevation. (Therefore, for the Missouri to flow into the Gulf of Mexico, it could not start from the Pacific.) I suspect they followed the river more as a navigation tool, perhaps they could go west a bit from where that ended and pick up the start of a new river, which they’d follow to the Pacific.

  8. says

    No, they really did think the Missouri…wait, you’re right, they knew the Missouri flowed into the Mississippi, so how could they think it also flowed into the Pacific? Even assuming they knew nothing about the mountains in between. I don’t know, but they did.

  9. says

    Ok you’re right, I’m wrong. Jefferson hoped they would find other rivers that did flow into the Pacific.

    his main objectives were centered around finding an all-water route to the Pacific coast and commerce. Before their departure, Jefferson’s instructions to them stated:
    The object of your mission is to explore the Missouri River, & such principle stream of it, as, by its course and communication with the waters of the Pacific ocean, whether the Columbia, Oregon, Colorado or any other river may offer the most direct & practicable water communication across this continent for the purpose of commerce.[32]


  10. says

    “The route of Lewis and Clark’s expedition took them up the Missouri River to its headwaters, then on to the Pacific via the Columbia River, and may have been influenced by the purported transcontinental journey of Moncacht-Apé by the same route about a century before. Jefferson had a copy of Le Page’s book detailing Moncacht-Apé’s itinerary in his library, and Lewis carried a copy with him during the expedition. Le Page’s description of Moncacht-Apé’s route across the continent, which neglects to mention the need to cross the Rocky Mountains, may be the source of Lewis and Clark’s mistaken belief that they could easily carry boats from the Missouri’s headwaters to the westward-flowing Columbia.”

  11. latveriandiplomat says

    IIRC, Naturalists of the time thought North America would be symmetrical, with another low, easy to cross mountain chain like the Appalachians as the source of the Missouri and then a piedmont and coastal plain on the other side with many navigable rivers to the Pacific .

    What L&C got instead was the larger and higher and more difficult to cross Rockies, where they almost died.

    In the end, following the Missouri takes you to some of the toughest terrain to get across, which is why the way west used by the Oregon Trail was the one found by later explorers.

  12. says

    And then even after they got over the Rockies…there were still more mountains.

    Flying over them west to east last May I got a particularly good look at how they go on and on and on and on. Huge mountains, then some plain, then huge mountains, then plain…over and over.

  13. Trebuchet says

    Ok you’re right, I’m wrong. Jefferson hoped they would find other rivers that did flow into the Pacific.

    And they did. It was just a little more difficult than they had hoped.

    Off to look up Moncacht-Apé now.

  14. Trebuchet says

    And yet another blockquote fail for me!

    Having looked up Moncacht-Apé, that’s quite interesting. Certainly Native Americans were crossing “the great divide” long before L&C.

  15. says

    Well they did literally “find other rivers that did flow into the Pacific” but that was short for “find other rivers that did flow into the Pacific that were easily reached from the easily reached source of the Missouri.” They didn’t find that at all.

  16. says

    Certainly Native Americans were crossing “the great divide” long before L&C.

    Yes, the Native Americans the exploring party met in the territory beyond the Missouri knew what was what but (if I’m remembering accurately this time) there wasn’t much travel and exchange with the Sioux because it’s such difficult terrain.

  17. Hj Hornbeck says

    All this talk of water flowing to oceans put me in mind of this.

    Look at all this on a map, and we see three places where continental divides intersect — points where a raindrop has to decide which of three oceans it might go to. One of these points lies near the Pennsylvania-New York border. Another is near Hibbing, Minnesota. Neither of these triple divides is very well defined. You’ll find no markers on them.

    But the third intersection lies in tourist country where geography is far more dramatic and identifiable. The northern divide meets the Rocky Mountain divide at aptly-named Triple Divide Mountain in Montana’s Glacier Park.

    I should dust off my passport sometime…

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