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An all-day, epic adventure linking together the most popular trails in the Patapsco River Valley.

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472' 144 m


36' 11 m


4,287' 1,307 m


4,289' 1,307 m



Avg Grade (2°)


Max Grade (14°)

Dogs Leashed

E-Bikes Not Allowed

No closure dates. Opt out of the river crossing into McKeldin during cooler weather because your feet will get wet and cold and stay wet and cold.


This is it, the legendary Tour de Patapsco, a 50+ mile Avalon to McKeldin adventure ride featuring the best of the beautiful Patapsco Valley State Park and surrounding areas. Be prepared for steep climbs, fast descents, gnarly rock gardens, hike-a-bike, a little bit of road riding, and a hike across the river.

The TdP is a challenging ride for experienced intermediate and advanced riders, testing the technical skills and endurance of even the most accomplished rider. Although at all times you'll be within minutes of suburban Baltimore/DC, you'll feel like you're on a remote backcountry adventure.

This ride is not for the faint of heart: the numerous short but steep climbs will wear you down and send you to bonktown if you're not attentive to your hydration and nutritional needs. Bring the GPS track, a printed map, nutrition, and anything required in case of mechanicals. Plan for 7-10 hours of riding depending on pace and amount of stopping. Consider a rehydration plan before embarking, using the convenience stores and/or park facilities along the route, or dropping water ahead of time.

The TdP was originally conceived by local mountain bikers out to link the Avalon/Orange Grove area of Patapsco to the McKeldin area using as much trail as possible. Way back when, the route was not only very challenging but also notoriously difficult to navigate, featuring plenty of unmaintained trails, some bushwhacking, and plenty of surprises along the way. Today, through the considerable efforts of MORE, in cooperation with the Park, along with thousands of volunteer hours, installation and improvement of numerous miles of hand-built singletrack have made the TdP easier to navigate and all-in-all more enjoyable than it once was.

This is an epic ride on every area mountain biker's bucket list.

Need to Know

The river crossing into McKeldin can be up to 2 feet deep following periods of heavy precipitation, but typically you can ride across. Water will be cold in the winter months and will surely get into your shoes, so you may want to opt out of this portion of the route when it's cold

An intermediate to advanced rider will finish the route in 7-10 hours so plan accordingly. The numerous short but steep climbs will wear you down. Bring adequate water, nutrition, repair supplies. While there are some convenience stores and park facilities along the way, you may consider dropping water/food at Old Frederick Road by the green metal bridge (you'll cross by at miles 14 and 38) and/or the end of the Old Court Road access road (miles 21 and 30). Note that the water inside the park is shut off during the winter season - if in doubt, contact the park.

Most of the trails are poorly marked. BRING GPS AND PRINTED MAP. Cell coverage may be poor in some areas. The MTB Project mobile app is recommended.


You'll start and end at the Lost Lake parking area. Ride the paved Grist Mill Trail to Vineyard Springs where you'll loosen up the legs with a gradual climb up to the Santee Branch Trail. Santee intersects the Saw Mill Trail which takes you to Hilltop Rd - cross to begin the Thistle Trail, which takes you to Thistle Rd; cross and continue on the Gray's Mill Trail to River Rd, short road ride to Frederick Rd.

The Cycle Mill bike shop is on the corner of River and Frederick. Make a left onto busy Frederick Rd, cruise downhill to a shared private driveway with a right-of-way to an access road/trail to Banneker Park. Climb up into Banneker. Follow the Outer Loop Trail around to cross Bryans Mill Way and continue on singletrack down to the Trolley Trail, a popular paved trail that climbs up to Oella Ave. At Oella and Westchester Ave there is a convenience store, a good place to refuel as the next water stop is 15 miles away.

Climb Westchester to Rest to Rockhaven Ave, which leads you to a trailhead on your left across the street from a ball field. After a bit, the singletrack will descend to the Oella Mill Race Trail, which you'll follow to a crossing underneath Rt 40. Proceed under the bridge, make a right up steep climb: this begins the technical "Devil's Horns" section of the Pickall area on the Pickall Trail.

Eventually, you cross the Cedar Branch, ride riverside singletrack then head uphill to the flowy Dogwood trail, which crosses Johnnycake Rd before ending on Dogwood Rd. Quick left after the bridge through the parking area onto Alberton Road, an old roadbed closed to traffic. Alberton eventually thins down to singletrack near Daniels Dam and takes you towards active railroad tracks. Follow the trail on the river side to go underneath the RR tracks alongside a creek, cross the creek, and begin the rocky climb on the Thru Trail.

The Thru Trail eventually dips underneath Woodstock/Old Court Rd. Cross a creek and make a right to begin an extended doubletrack climb to the old Fox Rock granite quarry. Continue along skirting the old Herndon Landfill before a fun descent to the North Branch of the Patapsco River which you'll soon cross into McKeldin at a section that is typically shallow enough to ride.

In McKeldin, follow the Switchback Trail up to the main parking areas where you'll find facilities and water. Continue through the parking area on the park road to pick up the Switchback Trail which leads to the Plantation Trail, a fun descent that brings you back down to riverside doubletrack before crossing the river back into Woodstock.

In Woodstock, follow the Thru Trail to the creek crossing that started the loop. Take the access road to Old Court Road, ride the bridge across the Patapsco, then make a left into the parking area just past the RR tracks -- the trailhead is at the downstream end. Follow the HoCo Thru Trail for several miles. Descend to the Old Main Line Trail doubletrack, then climb and descend the Switchplate Trail to cross Daniels Rd, then ride some of the church loop trails before taking Daniels Access Trail to Old Frederick Rd.

After crossing Old Frederick Rd, take Old Ranger Trail to the Hollofield area which has facilities and water. Ride the park roads to the rocky campground loop to a gravel BGE access road that leads to the paved Park Drive. Follow Park to Church down to Main Street (Frederick Rd) through historic Ellicott City (past a convenience store on your left) to River Rd.

River Rd becomes Illchester when you cross over the Patapsco. Immediately turn left, climb over the guardrail and follow the technical Old River Road/trail. This takes you past Bloede Dam on a gravel path. Enter Cascade Trail just before parking lot, then right on Garrett's Pass, follow to Morning Choice - West to Connector to Ridge Trail to Valley View East, back to Ridge Trail and down Waterbars to River Rd. Ride the road around the bend across the river, then Gunned takes you back to the start.

History & Background

The Patapsco River Valley is rich with history pre-dating the 1800s. Remnants of the old Grist Mill towns, granite quarries, and farming areas, along with evidence of the damage caused by Hurricane Agnes, can be found trailside. You'll ride through historic Ellicott City, founded 1772. The Patapsco Valley State Park was established in 1907.

For more history of the Park, see the Patapsco Heritage website.

For some historical perspective on the Tour de Patapsco, details of the original route can be found here. But note that much has changed since then(!):


Shared By:

Ken Lohr with improvements by John John

Trail Ratings

  4.7 from 6 votes


  4.7 from 6 votes
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