Maine Canoe Trips - Labor Day Weekend

My wife and I are looking to do a canoe trip up in Maine starting Labor Day weekend and continuing into the week. Does anyone know if places like Flagstaff Lake have campsites available on holiday weekends? I just don’t want to get to a first-come-first-serve campsite destination and be screwed by holiday weekend crowds.

There should be if you paddle to the remote sites. School is starting and with this year being this year there is more prep work for people to do

We have seen very few in the North Maine woods at paddle in sites. RV sites are different