Ohio River | Geography, History & Importance

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<span class="toc-extra-link selected link-gray-900 mt-15"> Introduction </span> <a class="toc-extra-link link-gray-900" href="https://www.britannica.com/place/Ohio-River/additional-info">References & Edit History</a> <a class="toc-extra-link link-gray-900" href="/facts/Ohio-River">Related Topics</a> </div> <div class="tlr-media-slider pb-10 mb-30"> <a class="section-header link-gray-900 font-serif font-14 font-weight-bold mb-10 mx-10" href="https://www.britannica.com/place/Ohio-River/images-videos">Images</a> <div class="slider js-slider position-relative d-inline-flex align-items-center mw-100 "> <div class="slider-container js-slider-container overflow-hidden d-flex overflow-hidden text-nowrap ml-15"> <a href="https://cdn.britannica.com/80/3080-050-AF84CCBD/Confluence-rivers-Mississippi-Ohio-Illinois-Cairo.jpg" data-href="/media/1/426008/2638" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/80/3080-004-CCCE5015/Confluence-rivers-Mississippi-Ohio-Illinois-Cairo.jpg" alt="confluence of the Mississippi and Ohio rivers" height="50" /> </a> <a href="https://cdn.britannica.com/64/241364-050-1C509DE0/Locator-map-Ohio-River.jpg" data-href="/media/1/426008/281444" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/64/241364-004-3BD94941/Locator-map-Ohio-River.jpg" alt="Ohio River" height="50" /> </a> <a href="https://cdn.britannica.com/70/147270-050-F3F1163C/cofferdam-construction-Olmsted-Lock-and-Dam-Ill.jpg" data-href="/media/1/426008/152913" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/70/147270-004-EBCF8E56/cofferdam-construction-Olmsted-Lock-and-Dam-Ill.jpg" alt="cofferdam" height="50" /> </a> <a href="https://cdn.britannica.com/00/116700-050-5745F1C4/Ohio-Marietta-confluence-Muskingum-River.jpg" data-href="/media/1/426008/112679" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/00/116700-004-18507061/Ohio-Marietta-confluence-Muskingum-River.jpg" alt="Marietta" height="50" /> </a> <a href="https://cdn.britannica.com/07/130007-050-E400EBDF/Ohio-River-Parkersburg-WVa.jpg" data-href="/media/1/426008/126897" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/07/130007-004-3D0A1514/Ohio-River-Parkersburg-WVa.jpg" alt="Ohio River" height="50" /> </a> <a href="https://cdn.britannica.com/07/71507-050-8BA8BF85/Railroad-bridge-Ohio-River-Bellaire-1872.jpg" data-href="/media/1/426008/208317" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/07/71507-004-39355D9E/Railroad-bridge-Ohio-River-Bellaire-1872.jpg" alt="Railroad bridge over the Ohio River" height="50" /> </a> <a href="https://cdn.britannica.com/75/12875-050-C1A06C06/Yeatmans-Cove-Park-Ohio-River-Cincinnati.jpg" data-href="/media/1/426008/9452" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/75/12875-004-7BBD8228/Yeatmans-Cove-Park-Ohio-River-Cincinnati.jpg" alt="Yeatmans Cove Park, Cincinnati, Ohio" height="50" /> </a> <a href="https://cdn.britannica.com/54/78754-050-DB3FF6B0/Ohio-Cincinnati-south-bank-River-1855.jpg" data-href="/media/1/426008/96937" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/54/78754-004-5CFFA774/Ohio-Cincinnati-south-bank-River-1855.jpg" alt="Cincinnati, Ohio" height="50" /> </a> <a href="https://cdn.britannica.com/62/3062-050-56E4A95A/basin-Mississippi-River-drainage-network.jpg" data-href="/media/1/426008/2614" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/62/3062-004-B3DA176D/basin-Mississippi-River-drainage-network.jpg" alt="Mississippi River basin and its drainage network" height="50" /> </a> <a 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Formed by the <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="confluence" href="https://www.merriam-webster.com/dictionary/confluence" data-type="MW">confluence</a> of the <a href="https://www.britannica.com/place/Allegheny-River" class="md-crosslink " data-show-preview="true">Allegheny</a> and <a href="https://www.britannica.com/place/Monongahela-River" class="md-crosslink " data-show-preview="true">Monongahela</a> rivers at Pittsburgh, it flows northwest out of <a href="https://www.britannica.com/place/Pennsylvania-state" class="md-crosslink autoxref " data-show-preview="true">Pennsylvania</a>, then in a general southwesterly direction to join the <span id="ref701570"></span><a href="https://www.britannica.com/place/Mississippi-River" class="md-crosslink " data-show-preview="true">Mississippi River</a> at <a href="https://www.britannica.com/place/Cairo-Illinois" class="md-crosslink " data-show-preview="true">Cairo</a>, <a href="https://www.britannica.com/place/Illinois-state" class="md-crosslink autoxref " data-show-preview="true">Illinois</a> (<em>see</em> <span class="link-blue media-overlay-link asmref" data-href="/media/1/426008/2638">photograph</span>), after a course of 981 miles (1,579 km). It marks several state boundaries: the Ohio–West <a href="https://www.britannica.com/place/Virginia-state" class="md-crosslink autoxref " data-show-preview="true">Virginia</a>, Ohio–Kentucky, Indiana–Kentucky, and Illinois–Kentucky. The Ohio River contributes more water to the <a href="https://www.britannica.com/place/Mississippi-state" class="md-crosslink autoxref " data-show-preview="true">Mississippi</a> than does any other tributary and drains an area of 203,900 square miles (528,100 square km). The river’s valley is narrow, with an average width of less than 0.5 mile (0.8 km) between <a href="https://www.britannica.com/place/Pittsburgh" class="md-crosslink " data-show-preview="true">Pittsburgh</a> and <a href="https://www.britannica.com/place/Wheeling-West-Virginia" class="md-crosslink " data-show-preview="true">Wheeling</a> (West Virginia), a little more than 1 mile (1.6 km) from <a href="https://www.britannica.com/place/Cincinnati" class="md-crosslink " data-show-preview="true">Cincinnati</a> (Ohio) to <a href="https://www.britannica.com/place/Louisville-Kentucky" class="md-crosslink " data-show-preview="true">Louisville</a> (Kentucky) and somewhat greater below Louisville.</p><span class="marker MOD1 mod-inline"></span><span class="marker PREMOD2 mod-inline"></span><p class="topic-paragraph">The <a href="https://www.britannica.com/place/Ohio-state" class="md-crosslink autoxref " data-show-preview="true">Ohio</a> is navigable, and, despite seasonal fluctuations that occasionally reach flood proportions, its fairly uniform flow has supported important <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="commerce" href="https://www.britannica.com/dictionary/commerce" data-type="EB">commerce</a> since settlement first began. Following destructive floods at <a href="https://www.britannica.com/place/Johnstown-Pennsylvania" class="md-crosslink " data-show-preview="true">Johnstown</a>, Pennsylvania, in 1889 and <a href="https://www.britannica.com/place/Portsmouth-Ohio" class="md-crosslink " data-show-preview="true">Portsmouth</a>, Ohio, in 1937, the federal government built a series of flood-control dams. While not developed for hydropower in Ohio, the river, kept at a navigable depth of 9 feet (3 metres), carries cargoes of <a href="https://www.britannica.com/science/coal-fossil-fuel" class="md-crosslink autoxref " data-show-preview="true">coal</a>, oil, steel, and manufactured articles. It has a total fall of only 429 feet (130 metres), the one major hazard to navigation being the <span id="ref701574"></span>Falls of the Ohio at Louisville, where locks control a descent of about 24 feet (7 metres) within a distance of 2.5 miles (4 km).</p><span class="marker MOD2 mod-inline"></span><span class="marker PREMOD3 mod-inline"></span><div class="assemblies"><div class="w-100"><figure class="md-assembly m-0 mb-md-0 card card-borderless print-false" data-assembly-id="281444" data-asm-type="image"><div class="md-assembly-wrapper card-media" data-type="image"><a href="https://cdn.britannica.com/64/241364-050-1C509DE0/Locator-map-Ohio-River.jpg" class="gtm-assembly-link position-relative d-flex align-items-center justify-content-center media-overlay-link card-media" data-href="/media/1/426008/281444"><picture><source media="(min-width: 680px)" srcset="https://cdn.britannica.com/64/241364-050-1C509DE0/Locator-map-Ohio-River.jpg"><img src="https://cdn.britannica.com/64/241364-050-1C509DE0/Locator-map-Ohio-River.jpg?w=300" alt="Ohio River" data-width="2000" data-height="1340" loading="eager"></picture><button class="magnifying-glass btn btn-circle position-absolute shadow btn-white top-10 right-10" aria-label="Zoom in"><em class="material-icons link-blue" data-icon="zoom_in"></em></button></a></div><figcaption class="card-body"><div class="md-assembly-caption text-muted font-14 font-serif line-clamp"><span><a class="gtm-assembly-link md-assembly-title font-weight-bold d-inline font-sans-serif mr-5 media-overlay-link" href="https://cdn.britannica.com/64/241364-050-1C509DE0/Locator-map-Ohio-River.jpg" data-href="/media/1/426008/281444">Ohio River</a><button class="js-more-btn d-none btn btn-unstyled font-12 bg-white js-content" aria-label="Toggle more/less fact data"><span class="link-blue">(more)</span></button></span></div></figcaption></figure></div></div><p class="topic-paragraph">The Ohio’s tributaries include the <a href="https://www.britannica.com/place/Tennessee-River" class="md-crosslink " data-show-preview="true">Tennessee</a>, <a href="https://www.britannica.com/place/Cumberland-River" class="md-crosslink " data-show-preview="true">Cumberland</a>, <a href="https://www.britannica.com/place/Kanawha-River" class="md-crosslink " data-show-preview="true">Kanawha</a>, <a href="https://www.britannica.com/place/Big-Sandy-River" class="md-crosslink " data-show-preview="true">Big Sandy</a>, <a href="https://www.britannica.com/place/Licking-River" class="md-crosslink " data-show-preview="true">Licking</a>, <a href="https://www.britannica.com/place/Kentucky-River" class="md-crosslink " data-show-preview="true">Kentucky</a>, and <a href="https://www.britannica.com/place/Green-River-Kentucky" class="md-crosslink " data-show-preview="true">Green</a> rivers from the south and the <a href="https://www.britannica.com/place/Muskingum-River" class="md-crosslink " data-show-preview="true">Muskingum</a>, <a href="https://www.britannica.com/place/Great-Miami-River" class="md-crosslink " data-show-preview="true">Miami</a>, <a href="https://www.britannica.com/place/Wabash-River" class="md-crosslink " data-show-preview="true">Wabash</a>, and <a href="https://www.britannica.com/place/Scioto-River" class="md-crosslink " data-show-preview="true">Scioto</a> rivers from the north. Chief cities along the river, in addition to Pittsburgh, Cairo, Wheeling, and Louisville, are <a href="https://www.britannica.com/place/Steubenville" class="md-crosslink autoxref " data-show-preview="true">Steubenville</a>, <a href="https://www.britannica.com/place/Marietta-Ohio" class="md-crosslink autoxref " data-show-preview="true">Marietta</a>, <a href="https://www.britannica.com/place/Gallipolis" class="md-crosslink autoxref " data-show-preview="true">Gallipolis</a>, Portsmouth, and Cincinnati in Ohio; <a href="https://www.britannica.com/place/Madison-Indiana" class="md-crosslink autoxref " data-show-preview="true">Madison</a>, <a href="https://www.britannica.com/place/New-Albany-Indiana" class="md-crosslink autoxref " data-show-preview="true">New Albany</a>, <a href="https://www.britannica.com/place/Evansville" class="md-crosslink autoxref " data-show-preview="true">Evansville</a>, and <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="Mount" href="https://www.britannica.com/dictionary/Mount" data-type="EB">Mount</a> Vernon in Indiana; <a href="https://www.britannica.com/place/Parkersburg" class="md-crosslink autoxref " data-show-preview="true">Parkersburg</a> and <a href="https://www.britannica.com/place/Huntington-West-Virginia" class="md-crosslink autoxref " data-show-preview="true">Huntington</a> in West Virginia; and <a href="https://www.britannica.com/place/Ashland-Kentucky" class="md-crosslink autoxref " data-show-preview="true">Ashland</a>, <a href="https://www.britannica.com/place/Covington-Kentucky" class="md-crosslink autoxref " data-show-preview="true">Covington</a>, <a href="https://www.britannica.com/place/Owensboro" class="md-crosslink autoxref " data-show-preview="true">Owensboro</a>, and <a href="https://www.britannica.com/place/Paducah" class="md-crosslink autoxref " data-show-preview="true">Paducah</a> in <a href="https://www.britannica.com/place/Kentucky" class="md-crosslink autoxref " data-show-preview="true">Kentucky</a>.</p><a class="link-module shadow-sm d-block qa-quiz-module" href="/quiz/water-and-its-varying-forms" data-link-module-iframe-link=""> <img loading="lazy" src="https://cdn.britannica.com/02/157502-131-7C5D3A67/water-glass-background.jpg" alt="water glass on white background. (drink; clear; clean water; liquid)" class="rounded-sm mr-15" width="70" /> <div class="line-clamp clamp-5"> <div class="module-title bg-green">Britannica Quiz</div> <div class="font-weight-semi-bold mt-5">Water and its Varying Forms</div> </div> </a><div class="one-good-fact-module"> </div><span class="marker MOD3 mod-inline"></span><span class="marker PREMOD4 mod-inline"></span><p class="topic-paragraph"><span id="ref225095"></span><a href="https://www.britannica.com/biography/Rene-Robert-Cavelier-sieur-de-La-Salle" class="md-crosslink " data-show-preview="true">René-Robert Cavelier, Sieur de La Salle</a>, is said to have been the first European to see the Ohio, in 1669, and he descended it until obstructed by a waterfall (presumably the Falls at Louisville). In the 1750s the river’s strategic importance (especially the fork at Pittsburgh) in the struggle between the French and the English for possession of the interior of the continent became fully recognized. By the treaty of 1763 ending the <span id="ref225096"></span><a href="https://www.britannica.com/event/French-and-Indian-War" class="md-crosslink " data-show-preview="true">French and Indian Wars</a>, the English finally gained undisputed control of the territory along its banks. When (by an <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="ordinance" href="https://www.britannica.com/dictionary/ordinance" data-type="EB">ordinance</a> of 1787) the area was opened to settlement, most of the settlers entered the region down the headwaters of the Ohio.</p><span class="marker MOD4 mod-inline"></span></section> <span class="md-signature font-12"><a href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419">The Editors of Encyclopaedia Britannica</a></span><span class="md-signature font-12">This article was most recently revised and updated by <a href="/editor/Michele-Metych/9760897">Michele Metych</a>.</span><span class="marker end-of-content"></span><span class="marker after-article"></span></div> <div id="chatbot-simplify-root"></div> <div id="chatbot-root"></div> </div> </div> </div> <div class="ai-dialog-placeholder"></div> </div> </div> <aside class="col-md-da-320"></aside> </div> </div> </div> </div> </article> </div> </div> </div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Topic","templateName":"DESKTOP","pageNumber":1,"pagesTotal":1,"pageId":426008,"pageLength":437,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-133/js/libs/jquery-3.5.0.min.js?v=3.133.36"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-133/dist/topic-page.js?v=3.133.36' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"D","adLeg":"D","userType":"ANONYMOUS","pageType":"Topic","pageSubtype":null,"articleTemplateType":"MEDIUM","gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":true} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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Ohio River | Geography, History & Importance | Britannica