An area from central Illinois into west-central and northwestern Ohio is the third most active region for the most powerful, long-tracked (at least 25 miles) tornadoes rated EF3 to EF5 in the United States, according to research conducted by the Storm Prediction Center. In fact, Van Wert County has had the highest frequency of these large long-tracked tornadoes, more than anywhere in the Ohio Valley and Mid-Mississippi Valley.
Ohio has only had four F5 rated tornadoes since 1950, and two of those were in southwest Ohio. Both occurred on the same day, April 3rd, 1974. (The Fujita scale (F) was replaced by the Enhanced Fujita scale (EF) after January 2007.) This, of course, was the day of the infamous Xenia tornado. The other EF5 struck on the west side of Cincinnati in Hamilton County.