Antique Real Photo Postcard. Identified as Lake Winnipesaukee in New Hampshire. Published by R.C. Co. Birch Bark Border series. Copyright 1906. Undivided back, unused. Condition: This is an original photo postcard, not a copy or reproduction. It is in excellent condition. Comments: Lake Winnipesaukee is the largest lake in the U.S. state of New Hampshire, located in the Lakes Region at the foothills of the White Mountains. It is approximately 21 miles long and from 1 to 9 miles wide, covering 69 square miles, or 71 square miles when Paugus Bay is included, and has a maximum depth of 180 feet.