<a href="https://en.wikipedia.org/wiki/American_frontier" id="mwfQ" rel="mw:WikiLink" title="American frontier">American Old West</a>: On the <a href="https://en.wikipedia.org/wiki/Sonoita_Creek" id="mwfg" rel="mw:WikiLink" title="Sonoita Creek">Sonoita River</a> in present-day southern <a href="https://en.wikipedia.org/wiki/Arizona" id="mwfw" rel="mw:WikiLink" title="Arizona">Arizona</a>, the United States Army establishes <a href="https://en.wikipedia.org/wiki/Fort_Buchanan,_Arizona" id="mwgA" rel="mw:WikiLink" title="Fort Buchanan, Arizona">Fort Buchanan</a> in order to help control new land acquired in the <a href="https://en.wikipedia.org/wiki/Gadsden_Purchase" id="mwgQ" rel="mw:WikiLink" title="Gadsden Purchase">Gadsden Purchase</a>.