Mercer County leads the state for the lowest rate of unemployment in the state. The Ohio Department of Job and Family Services reports Mercer County had 3.3 percent unemployment in May. This was an increase from 2.7 percent in April. Auglaize County also increased slightly from 3.3 to 3.7 percent. Van Wert County reported 3.7 percent. Darke County had 4 percent. The state of Ohio's rate of unemployment rose slightly from 4 percent to 4.2 percent.