The lake contains at least 253 islands, half of which are less than a quarter-acre in size (list of islands) and is indented by several peninsulas, yielding a total shoreline of some 288 miles. The driving distance around the lake is 63 miles. It is 504 feet (153 m) above sea level. Winnipesaukee is the third-largest lake in New England after Lake Champlain and Moosehead Lake.
Outflow is regulated by the Lakeport Dam (in Lakeport, New Hampshire) on the Winnipesaukee River.
Lake Winnipesaukee has been a tourist destination for more than a century, especially for residents escaping the summer heat of Boston and New York City. The Native American name Winnipesaukee means either "smile of the Great Spirit" or "beautiful water in a high place". At the outlet of the Winnipesaukee River, the Winnipesaukee Indians, a subtribe of the Pennacook, lived and fished at a village called Acquadocton. The site is today called The Weirs, named for the weirs colonists discovered when first exploring the region.
Winnipesaukee is a glacial lake and an unusual one at that, since the last glaciation actually reversed the flow of its waters. Draining the central portion of New Hampshire, it once flowed southeast, leaving via what is now Alton Bay toward the Atlantic Ocean. When glacial debris blocked this path, flow was redirected westward through Paugus Bay into the Winnipesaukee River. The latter flows west from the lake and joins the Pemigewasset River in Franklin to form the Merrimack River, which flows south to Massachusetts and into the Atlantic.
Center Harbor witnessed the first intercollegiate sporting event in the United States, as Harvard defeated Yale by two lengths in the first Harvard-Yale Regatta on August 3, 1852. The outcome was repeated 100 years later when the schools celebrated the centennial of the race by again competing on Lake Winnipesaukee.
French President Nicolas Sarkozy took his first vacation in office in August 2007 at Wolfeboro on the lake.
Lake Winnipesaukee was also where the eponymous Lake Winnipesaukee mystery stone was found.
The communities that surround the lake, clockwise from the southernmost town, are:
The paddlesteamer Mount Washington, named after the highest of New Hampshire's White Mountains, was launched in spring 1872 to carry mail, goods, and passengers on Lake Winnipesaukee, under the flag of the Boston and Maine Railroad. With a hull length of 178 feet and a beam of 49 feet she appeared as a typical representative of the North American sidewheelers around the second half of the century and was the largest steamer on the lake at that time. The huge paddle wheels were driven by a single-cylinder steam engine of 450 HP at approximately 26 RPM. The power was transferred from the vertical single cylinder to the wheel shaft by the walking beam, high above the upper deck, oscillating in the frequency of the paddle wheels. Known as "The Mount", her kitchen and restaurant service became famous.
On December 23, 1939, a nearby railroad station caught fire from an overheated stove. The fire soon spread to the ship, tied at the dock, and destroyed it. Efforts to cut the Mount loose were to no avail as it was a time of extremely low water and the hull was stuck fast in the mud of the lake bottom. Soon after, a local company was formed to build a new ship. Since Europe was already at war, obtaining steel was impossible. Instead, they purchased an old sidewheel vessel on Lake Champlain: the Chateaugay, a 203-foot, iron-hulled sidewheeler that was being used as a club house for the Burlington yacht club. It was cut into sections and transported to Lake Winnipesaukee on rail cars. A new twin-screw vessel was designed for the hull being welded back together at Lakeport. Powered by two steam engines taken from another ocean-going yacht, the new MS Mount Washington made her maiden voyage on August 15, 1940.
Two years after her launch, the new Mount's engines were removed for use in a navy vessel during World War II. After the war, the Mount Washington returned to the water. The ship was a success in the post-war tourist boom.
In 1982, the Mount was cut open and extended with an additional 20-foot hull section to add larger lounge and food service facilities. Still popular, it makes one or two round trips on the lake per day during the summer season, as well as numerous dinner dance cruises in the evenings.
The water temperature typically reaches the upper 70s F (around 25°C) in late July and cools into the 60s (around 18°C) in September. Several days of hot, humid weather at the height of summer can bring the water temperature well above 80°F (26°C.) It normally freezes during the last week of December. Ice thickness during a typical winter can be in excess of 18 inches in many parts of the lake.