Missouri River Valley
...that at 2,300 miles (3,700 km) long the Missouri River Valley drains one-sixth of the United States, and is the longest river valley on the North American continent?
...that at 2,300 miles (3,700 km) long the <b id="mwEIY"><a href="./Missouri_River_Valley" id="mwEIc" rel="mw:WikiLink" title="Missouri River Valley">Missouri River Valley</a></b> <a href="./Drainage_basin" id="mwEIg" rel="mw:WikiLink" title="Drainage basin">drains</a> one-sixth of the <a href="./United_States" id="mwEIk" rel="mw:WikiLink" title="United States">United States</a>, and is the longest <a class="mw-redirect" href="./River_valley" id="mwEIo" rel="mw:WikiLink" title="River valley">river valley</a> on the <a href="./North_America" id="mwEIs" rel="mw:WikiLink" title="North America">North American</a> continent?