Chillicothe gas prices late last Friday (Feb. 15) went up 10 more cents from last Monday's price, from $3.47 per gallon of regular unleaded to $3.57 per gallon. It has been exactly one month since Chillicothe's gas prices began their continuous climb from $2.93 per gallon. In that span, gas prices have gone up an average of $0.0206 per day.