You Could Have Tripped Over It
I almost did, too...this double-headed marker is for the Presumpscot River Trail that runs from the western edge of Portland into Falmouth and down to right near Mackworth Island. The marker for Presumpscot River Trail and Sebago to the Sea is partially hidden in the summer grass at the corner of Auburn Street and Washington Avenue Extension...a softball throw from Summit Street.
Thanks for taking a run at identifying the location--and, gotta say, the idea of a meandering paddle down the Presumpscot sounds great. From the double-marker, you drive around a slow curve, take a right and look for the next 6" x 6" sign, park, drop your kayak or canoe in the water and off you go. It's a bit of a haul back to your car, so you'll probably want to have another vehicle parked down stream to ferry you and your boat(s) back up to the put in.
Get out there, this summer and enjoy what Portland and vicinity has to offer.
We'll continue the Portland Quest next Tuesday. Thanks for playing along, and have a great weekend!