(Whitewater Valley)--Gas prices have risen seven cents since Monday of last week in Wayne County.  The average price of a gallon of gas on Monday in Wayne County is $5.21, according to AAA.  Union County now has the highest average price in Indiana with the exception of two Chicago-area counties.  Union County is at $5.27.  Our area's "cheapest" gas is in Darke County at $5.04.