Lake Wentworth is located in the Lakes Region of east central New Hampshire, south of the White Mountains. More specifically, it lies in Carroll County, wholly within the boundaries of the township of Wolfeboro.
The lake is nearly four miles long from east to west and 2.5 miles wide from north to south. The average depth is 21 feet, with a maximum depth of about 83 feet at full lake level.
The water area is 3037 acres or, counting islands, 3172 — about five square miles. The shoreline is slightly over 13 miles long. A single outlet to the west, Smith River, drains into Crescent Lake and, from there, into Wolfeboro Bay on Lake Winnipesaukee.
The surface is about 534 feet above sea level, some 30 feet higher than Lake Winnipesaukee.
The lake water volume flushes completely approximately every other year (0.74 times per year as calculated by the 2012 Wentworth-Crescent Watershed Management Plan).
Fourteen streams drain directly into Lake Wentworth, descending from a horseshoe-shaped ring of low hills lying two to four miles back from the shore to the north, east, and south. Beginning at the northwest corner of the lake and moving clockwise, these streams are: Harvey Brook, Hersey (Tyler) Brook, Fernald Brook, Willey Brook, Ryefield Brook, Claypit Brook, Frost Brook (a tributary of Claypit), Whitton Brook, Warren Brook, Townsend Brook, Breezy Brook, Red Brook, and Heath Brook.
Hersey Brook is the outlet for Sargent’s Pond, a mile north of Wentworth, and Willey Brook (the largest subwatershed) is the outlet for Batson’s Pond, some four miles to the northeast.
Warren Brook to the east, being the inlet farthest from the outlet, is “the head of the lake.”
Warren, Ryefield, and Heath brooks are deep enough for small watercraft navigation in some seasons.
What was called Lily Brook was transformed into a bog in the early 1940s through the construction of Wentworth State Park on the eastern shore of the lake.
The inlet streams account for 76% of the water entering Lake Wentworth. Additional inputs to Lake Wentworth are from rainfall (25.3%) and direct runoff (0.3%). It is estimated that 82.5% of the water entering Lake Wentworth flows directly into Crescent Lake, with 7.5% evaporating and 10% entering groundwater.
Lake Wentworth has 20 islands scattered across the waterbody, including eight currently inhabited islands (Bass, Cate, Loon, Mink, Poplar, Sister, Trigg’s, and Turtle), two previously inhabited islands (Brummitt and Stamp Act), 10 uninhabited islands (Flo, Goose, Joe, the two Jockey Caps, Min, Wal, Fanny, Governor’s Rock, and Gull Rock).
Located in the middle of Lake Wentworth, Stamp Act Island is approximately 4,000 feet long at its widest, and 1,200 feet wide, with 12,000 feet of shoreline. The island was purchased as protected land by The Nature Conservancy in 1977 through the impressive fundraising efforts of the Lake Wentworth Association and community residents.
Crescent Lake and Lake Wentworth are controlled by a dam built in 1855 by the Lake Company at the outlet of Crescent Lake. This dam was originally built to control water flow to mills in Wolfeboro Falls. The Smith River was also dredged, which allowed the water level of Lake Wentworth to be manipulated three to four feet by operation of the Crescent Lake dam.
Wentworth is situated within a temperate zone of converging weather patterns from the hot, wet southern regions and the cold, dry northern regions, which causes various natural phenomena such as severe thunder and lightning storms, hurricanes, heavy snowfalls, and tornados. The largest tornado in New England was recorded on July 24, 2008, as it mowed down a 50-mile swath, cutting across Wolfeboro and Lake Wentworth.
The area experiences moderate rainfall and snowfall, averaging 40.6 inches of precipitation annually. Temperature ranges from minus 35 °F to 102 °F, with an average of 20.6 °F in January and 70 °F in July. The growing season extends from May to September over a 120-day period. Winter extends from December to March, with ice-out historically occurring from mid-April to early May. However, recent years have seen a steady shift to earlier ice-outs, with few now extending much into April.
As far back as the Colonial Period, Lake Wentworth bore the less romantic appellation “Smith’s Pond.” Smith is said to have been a hunter. His name was also given to the outlet, Smith River.
The White Mountains: A Handbook for Travellers in 1876 perhaps first suggested the change: “In view of the beauty of the lake and its historic memories, it would be a great improvement to change the prosaic name of Smith’s Pond to the more stately and significant one of Lake Wentworth.” In 1888 the same guidebook referred to the lake by its present name, parenthetically adding “formerly Smith’s Pond,” but did not make the alteration on its maps. In fact, the earliest cartographic use of the new name appears to date from 1895, and even as late as the 1920’s United States Geological Survey maps still used “Smith’s Pond.”
Natural pond controlled by a dam at the outlet of Crescent Lake
Altitude: 534 feet
Size 3037 acres
Shoreline: 13 miles
Tributary to Smith River
Max depth: 83 feet at full lake
Average depth: 20 feet
Fish species: Smallmouth bass, largemouth bass, chain pickerel, while perch, yellow perch, lake whitefish, common sunfish, horned pout, white suckers, club suckers, fallfish, American eel, smelt, golden shiners
Public boat access: Mast Landing on Crescent Lake to Smith River
Trophic status: oligotrophic