Polk County recently opened Marshall Hampton Reserve, 1,173 acres of wildlife and natural beauty, near Thornhill Road and County Road 540 in Polk County. There is no admission to enjoy the two unpaved trails: the 3.5 mile Acorn Hammock Trail and the 2.5 mile Osprey Overlook Trail. The Reserve is open daily from 5:30am to 8pm during daylight saving time and 6:30am to 6:30pm during standard time.
An article in the Lakeland Ledger offers more information http://www.theledger.com/article/20110917/NEWS/110919385.