Patapsco Valley State Park — McKeldin Trail

Patapsco Valley State Park spans more than 16,000 acres along the Patapsco River through Howard and Carroll Counties, Maryland. The McKeldin Area at 11676 Marriottsville Rd, Marriottsville — approximately 30 miles west of Baltimore via I-695 and Marriottsville Road — is the park's most scenic access point, preserving a section of the Patapsco River gorge where the river braids across greenstone and mica schist bedrock in a series of Class II rapids and boulder-strewn channels.

The primary trail option from the McKeldin Area is a 6.2-mile loop combining the McKeldin Switchback Trail and the River Road Loop. The loop begins from the main parking area, descending via a series of switchbacks through mixed hardwood forest over approximately 350 feet of elevation loss to reach the river level. At the river, the trail follows the Patapsco upstream through a narrow gorge corridor where the water alternates between calm pools and whitewater rapids. Rock-hopping and potential wet crossings add engagement, particularly during spring high water. Waterproof boots are strongly recommended from March through May.

The return ascent via switchbacks regains most of the elevation in a concentrated 0.5-mile climb. The trail surface is primarily compacted dirt and embedded rock, with boardwalk sections at the lowest river crossings. Side trails connect to the park's equestrian trail network and longer ridge routes. Wildlife sightings along the river corridor include belted kingfisher, great blue heron, osprey, and beaver. A per-person day-use fee of $5–$6 applies at the McKeldin entrance gate; facilities include a large parking area, picnic tables with river views, and restrooms. Seasonal kayak and tube launch access at the McKeldin rapids is also available.