This is Marcy Dam Marcy Dam is a simple wooden structure, built originally for purposes associated with logging before the area became the High Peaks Wilderness. It is where the main trail from Adirondak Loj crosses Marcy Brook. It is a major camping area and throughfare when hiking in the area.
This image is from the presentation "The Adirondack High Peaks Region and Andrew's 46er Page - Marcy Dam over the Years".