Rivnuts from Homestead, PA on 8/31/2024 9:42:45 PM:
While the various trail closures and detours on the GAP and C&O trails are cited in various web sites, I'll identify the significant ones that I encountered in my trip from Pittsburgh to DC last week.
GAP Trail - Between mile markers 95.5 (Dawson Trailhead) and 92 (Adelaide Blue Canoe RV Park). The trail is closed between these locations for construction. A shuttle service for the riders and their bikes is provided for free between these locations. The service is provided 7 days a week from 7:30 AM to 7:00 PM. Expect the shuttle to require 30 to 45 minutes. I do not recommend trying to ride your bike along the detour on the roads between these points.
C&O Towpath - At C&O mile 134.3, Polly Pond Creek, the trail is closed for a bridge failure over the creek. There is a detour sign at Lock 56 (mile marker 136.2) that directs you across a causeway up to and over the WMRT onto Pearre Road to Deneen Road and back to the Towpath at Cohill Station (mile marker 131.3) This an onerous and likely unnecessary detour. Alternately, I was able to leave the Towpath up onto the parallel WMRT and avoid the Towpath bridge outage. Where there are signs along the WMRT itself approaching Hancock stating that sections of the WMRT may/are closed, the WMRT was open far enough for me to bypass the Towpath bridge closure and return to the Towpath toward Hancock. This is a much better detour. I recommend you stop oncoming riders from Hancock and inquire their route going upriver from Hancock on the Towpath and WMRT.
C&O Towpath - There is a detour on the Towpath at mile marker 106 for construction at Dam 5. This is a short detour but requires going up/down two flights of wooden stairs. There are planks provided along the stair steps to push/roll your bike along the steps but this is very difficult with a fully-loaded bike. You may have to unload/reload your bike to navigate the stairs or have another rider assist you.
C&O Towpath - There is construction work along the towpath between miles 11 and 11.5 requiring its closure. The detour takes you up onto and along a public road before returning to the Towpath. There are shallow steps to the road but there are earthen paths adjacent to the steps to facilitate taking your bike up and down.
There are a few, very minor detours for washouts along the Towpath but these are very short and inconsequential.
Hopefully this info helps. You can find more details about these closures/detours on the GAP and NPS C&O Canal websites.