Great Falls

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October 27

Great Falls Fall Color

Welcome back to C&O NHP! Once again, due to park regulations we require advance registration with payment. Pre-registration is currently open at the moment (again, due to cancellations); click here to register. If after you've registered you realize you won't be able to attend, please notify us in advance so others can attend. Note that here will be no day-of registration at the event (nor will there be refunds). There will be compasses and epunches available to those who requested them during pre-registration, but GPS watches will not be available at this event.

On Sunday, only pre-registered orienteers will be able to start on their course, anytime between 11 - 1:30, and must be back no later than 3pm.

Course Information: Provisional course stats are below, but they are subject to change. These courses are carefully designed to avoid areas that the National Park Service has designated as sensitive.

Speaking of sensitive areas, the NPS has asked us to remind all participants of the following:

  • Participants should follow compass bearings as close as possible. Participants should not take shortcuts: approved routes are designed specifically to avoid sensitive habitats and known invasive plant populations that may facilitate human-facilitated spread of seeds and berries.
  • Participants should avoid any and all standing water, including seeps, springs, wetlands, and streams. Amphibian diseases have been documented in the area, and human-facilitated movement of such fungal pathogens from habitat to habitat can cause massive die-offs in amphibian species.
  • All participants must avoid stepping in streams and should try to minimize impacts to stream bank vegetation and soils.

Save $8 - Just $9 For A Large Pizza Once Again, Back by Popular Demand: Post-Race Potomac Pizza Palooza! After your race, take advantage of a 1/2 price pizza deal at a nearby restaurant, Potomac Pizza. Normally $17 for a large cheese and tomato pizza, just wave your QOC map and you'll get this 8 slice pizza for just $9, and additional toppings are only $1 each. There's seating for everyone at this friendly local place with a full menu, free soda refills, and it's no problem to go "as you are" post-race. There's plenty of room to go over your map and routes and meet up with your fellow orienteers. The address is 9812 Falls Rd in Potomac; to get there, just take a left at the stop sign as you exit the park, and in less than 2 miles take a left just before River Road into the Potomac Promenade parking area. Directions are also shown in the Event Locator Map.

Have any questions? Just use our Contact Us form and ask away!

Rain Policy: QOC events take place rain or shine - as long as we have permission to hold the event. Some parks may revoke our permit based on rain, but Great Falls is not one of them. However, we take the possibility of lightning strikes during thunderstorms seriously. Although the forecast is not currently predicting any significant chance of lightning, [Update 8pm Sat: in fact, the sun may come out by around noon according to one recent forecast] at the event our Event Directors will temporarily suspend all activity and direct participants to their cars or nearby buildings if a significant threat materializes. But don't wait for us to say something: all orienteers should be savvy enough on their own to know about basic lightning safety; an example from the CDC for hikers is here.


C&O NHP (Great Falls MD), Great Falls Tavern, Potomac, MD (Classic)

RegistrationPre-registration is required; click here to register and pay.
Start TimesStart any time between the specified times (usually 11am - 1:30pm).
ScheduleSunday, October 27
11:00 am - 3:00 pmClassic:
Event Director:Greg Lennon
Event Director:Kathleen Lennon
Course Designer:Nadim Ahmed
Location Details

C&O NHP (Great Falls MD)
Great Falls Tavern
Potomac, MD
Google Map

From I-495, Maryland: Take exit 41 (Carderock/Great Falls, MD), follow Clara Barton Parkway to the end. At the stop sign, turn left onto MacArthur Blvd. Follow MacArthur ~3.5 miles to the park entrance booth. MacArthur Blvd. ends at the park.

From I-495, Virginia: Cross into Maryland over the American Legion Bridge (beltway inner loop) and take exit 41 (Clara Barton Parkway) Westbound, staying left at the fork. Follow Clara Barton to the end. At the stop sign, turn left onto MacArthur Blvd. Follow MacArthur Blvd ~3.5 miles to the park entrance booth. MacArthur Blvd. ends at the park.

After paying the park entrance fee, park in the large lot to the right (north) of the roundabout, then walk south back past the roundabout and beyond the Tavern to find our registration area.

Printable detailed maps showing the parking/registration area and the route to the Pizza Palooza are available here.

Course DetailsClassic
Course NameLength (km)Climb (m)No. Controls
Beginner 3609
Intermediate 5.619013
Medium Advanced 5.923514
Long Advanced 8.831023
Course NotesClassic

For all courses there will be an approximately 350m walk to the start. Allow 5-10 minutes for the walk which goes up a rocky trail into the forest where the footing is better. Wet conditions may make footing slippery, so be careful both on- and off-trail.

Great Falls Park is busy with many other visitors. Please share the trails courteously. There are also sensitive areas marked with orange hash on the map. Please stay out of these at all times—whether you’re competing or not.


  • During your course, do not run or walk on or along any paved roads.
  • The park has asked that competitors and spectators avoid areas of deep pits/ditches left over from mining activity.
  • Park managers report that wildlife monitoring traps had been set up in the spring and may still be present. Orienteers should stay clear of these traps and any associated metal stakes. While field checking and course setting, none were seen but it’s still possible that some may be present.
  • Participants should avoid all standing water, including steeps, springs, wetlands and streams. Avoid stepping in streams and minimize damage to streambank vegetation and soils.

In agreement with park management, three non-standard courses will be used with approved control locations.

  • There are three courses (Beginner, Intermediate, Advanced). Advanced orienteers who feel they are unlikely to be able to complete the Advanced course have a ‘safety option’ that is shorter in length (Medium Advanced) but shares a majority of the same approved legs as the Advanced course.
  • Beginner courses are primarily on trails however a few controls will be just off trail within eyesight.
  • For Intermediate and Advanced courses, the park service adjusted a few planned control locations such that they are being placed a farther distance away from mapped features than is normal. These few controls may appear to not be on the feature listed in the clue description, nor on any other feature. Go to the center of the mapped circle on these.
  • The Intermediate course will be challenging for those new to running Orange. It would be better to move up to Orange/Intermediate at a different event than at this one.
  • The Advanced course has a butterfly loop. Competitors will visit control #117 twice. Other parts are “sprinty”, where an ability to plan ahead and accurately change directions quickly will produce the best results.

The terrain continues to change since the many years ago when club member David Linthicum created the excellent Great Falls, MD map for local and national competitions:

  • Vegetation has changed the most. Generally, the beech tree saplings have been spreading and new copse have emerged. Map updates for these trees have been made near controls and on leg routes but it’s highly likely that competitors will find areas still needing revision.
  • Invasive stilt grasses continue to spread through the park. They are more prevalent in the southeast parts of the park. They are dying off for the season but will pose a hazard since they are still tall enough to obscure deadfall and uneven footing. Stilt grass is not mapped.
  • Rootstocks have been updated where found by eliminating old ones and adding new ones—they have an approximate minimum height of 1.5m.
  • Small areas mapped as distinct open terrain inside the forest were mapped long ago and most of them have not been validated.
  • Additional cairns have been found. Where approximately 1m tall, they have been mapped with the cairn symbol. Some smaller and broken cairns have been mapped as rocky ground with 3 black dots.
  • North/South meridian lines are now 300m apart.

Entry FeesIndividual Entries

Note: juniors = under 21

Club Member, adult Club Member, junior Non-Member, adult Non-Member, junior
Epunch Owner $5 $5 $10 $5
Epunch Borrower $10 $5 $15 $10

Team or Group Entries

Participants are welcome to compete together as a single team entry. Teams containing one or more nonmembers are charged the nonmember individual rate. Teams containing one or more adults are charged the adult individual rate. For teams to receive member or junior rates, all members of the team must be members or juniors, respectively. Each extra team map beyond the first is an additional $2. Individuals or teams desiring to compete on a second course can do so for a reduced fee of $2/map.

Important Notes
  • If you wish to become a QOC member you should join online in advance via this webpage (which also explains the member benefits). Membership is completely optional.
  • Most of our events use an 'epunch' timing chip for electronic timing. Individuals or groups without their own epunch pay a higher entry fee (see above), which includes the loan of an epunch for that event. Loaned epunches that are lost incur a $40 replacement fee. Epunches (also known as SI-cards or finger sticks) can be purchased from online vendors as described here.
  • Former QOC members who have let their membership lapse pay non-member fees.
  • Compasses are available at no charge, but if lost incur a $15 replacement fee.
  • Please provide collateral (driver's license or car keys) when borrowing a compass or epunch.
  • For additional safety, whistles are available for sale at $1/each.
  • Free beginner instruction is always available - just ask at the registration table.