The National UFO Reporting Center is located in Davenport, Washington. That organization has collected over 30,000 reports of Unidentified Flying Objects in U.S. airspace in the past fifteen years. Those reports are sorted by U.S. counties at http://labs.slate.com/articles/ufo-sightings-map/
McDonald County, Missouri, reported 26 sightings per 100,000 - actually a very paltry number considering that the county's population would have to quadruple to be anywhere near 100,000. Local pride should remain be in tact, however, because it still had more than any of the adjoining counties in Missouri, Oklahoma, or Arkansas.
Lock and load, Arizona. Lock and load!