Mill Springs Grist Mill Opens for Summer Tours – Mill Springs Mill Park, 9155 Hwy 1275 N, Monticello, KY, 9am-5pm weekends and holidays. Mill Springs Grist Mill Opens for 2019 Summer Season May 25, 2019. The Mill Springs Grist Mill will be open from 9am till 5pm on Saturdays, Sundays and Holidays beginning May 25th and will continue seasonal operation through September 8th. Guided tours will be provided every half hour, with corn grinding demonstrations at 2:00pm, Sat., Sun. & holidays. Call 606-679-6337 or visit www.lrn.usace.army.mil/About/History/Mill-Springs-Park/ for additional information.