The town includes the villages of North, South and East Waterboro, in addition to the village of Lake Arrowhead, which comprises one third of Waterboro's population.
Lumbering began to thrive here about 1764. Captain John Smith from Kittery was the first permanent settler, arriving in 1768. On March 6, 1787, the Massachusetts General Court incorporated the township as Waterborough. In 1790, Old Corners became the site of the Court of General Sessions, although in 1805 the county seat shifted to Alfred. In 1895, the name was shortened to Waterboro.
With land particularly suited for livestock grazing, agriculture became a principal industry. The town had many cattle and dairy farms. The Portland and Rochester Railroad passed through Waterboro and connected to Rochester, New Hampshire in 1871, helping spur development. Rivers and brooks provided water power to operate mills. Several sawmills were established, and by 1886 the town produced about of lumber annually. Other businesses included the Ossipee Manufacturing Company at the Little Ossipee River, which made blankets, and the Steam Mill Company at South Waterboro, which made wooden boxes. In 1922, the Goodall-Sanford Mills built in Waterboro village a spinning mill, taken over by a patent leather manufacturer that operated from 1939-1982.
Fire twice devastated the town. In 1911, a large portion of South Waterboro burned. Then during the Great Fires of 1947, three-quarters of Waterboro's land area burned, including the town center and 90% of the cottages on Little Ossipee Lake. Today, Waterboro's lakes remain a popular recreation area. The town is home to the 2,140 acre (866 hectare) Waterboro Barrens, one of the largest and best preserved pitch pine barrens in Maine.
Waterboro is crossed by U. S. Route 202 and state routes 4 and 5. It borders the towns of Alfred to the southwest, and Lyman to the southeast, Hollis to the northeast, Limerick and Limington to the north, Newfield to the northwest, and Shapleigh to the west.
As of the census of 2000, there were 6,214 people, 2,211 households, and 1,704 families residing in the town. The population density was 111.9 people per square mile (43.2/km²). There were 2,828 housing units at an average density of 50.9/sq mi (19.7/km²). The racial makeup of the town was 98.66% White, 0.11% African American, 0.32% Native American, 0.21% Asian, 0.14% from other races, and 0.55% from two or more races. Hispanic or Latino of any race were 0.68% of the population.
There were 2,211 households out of which 43.0% had children under the age of 18 living with them, 64.3% were married couples living together, 8.6% had a female householder with no husband present, and 22.9% were non-families. 15.9% of all households were made up of individuals and 5.7% had someone living alone who was 65 years of age or older. The average household size was 2.81 and the average family size was 3.15.
In the town the population was spread out with 30.8% under the age of 18, 6.5% from 18 to 24, 35.9% from 25 to 44, 19.8% from 45 to 64, and 7.0% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 102.0 males. For every 100 females age 18 and over, there were 99.5 males.
The median income for a household in the town was $43,234, and the median income for a family was $46,667. Males had a median income of $33,583 versus $21,904 for females. The per capita income for the town was $17,813. About 3.4% of families and 6.1% of the population were below the poverty line, including 7.4% of those under age 18 and 7.8% of those age 65 or over.