Millennium Trail at Bernheim Arboretum and Research Forest

The Millennium Trail is the longest and most demanding hike at Bernheim Arboretum and Research Forest, a large private nature preserve at 2155 Clermont Rd in Clermont, Kentucky, about 25 miles (40 km) south of Downtown Louisville. The drive takes around 35 minutes via I-65, and there is no public transit. Admission and hours vary: weekdays were free and weekends about $5 USD per car according to an undated guide, so visitors should confirm at bernheim.org or by phone at 502-955-8512. Hikers register at the Visitor Center or trailhead, and the trail page asks for an early start, no later than 9 am from November to March, so the full loop finishes in daylight. Visitors should follow the rule posted on site.

The route is a 13.75-mile (22 km) loop that typically takes 6 to 7 hours. It crosses rolling to steep forested hills across the Knobs, with repeated climbs and descents and a difficult overall rating. Because of the distance, it is a hard hike by length rather than by any single technical section. Surfaces are mainly dirt forest trail with roots, rocks and stream crossings, and the route is largely shaded under hardwood canopy, with some open meadow and lake edges. Mud is common after rain.

The loop passes through varied habitat, including upland forest, ridges and hollows, and views across the preserve. Hikers can shorten the day by using the preserve's connecting trails and roads and returning to the Visitor Center, which makes the Visitor Center the natural bail-out point. Water should be carried in quantity, about 3 liters for the full loop, along with food, since services are only near the Visitor Center. A map and a charged phone are important, and a headlamp is prudent in the short days of late fall and winter. October to November and March to May offer the most comfortable weather, while summer heat and humidity make the long loop taxing.