Mercer County has Ohio's lowest rate of unemployment according to figures releaed this week by the Ohio Department of Job and Family Services. Mercer County reported 3.2 percent unemployment for July. Auglaize County had 3.8 percent. Van Wert County reported 4 percent unemployment.The highest rate of unemployment was recorded by Lucas County with 7.4 percent. Ohio’s unemployment rate was 4.5% in July, up from 4.4% in June