The Kennebec River valley was attacked and burned in 1676 during King Philip's War, then again in 1689 at the outset of King William's War, and was not resettled until after the 1713 Treaty of Portsmouth. The town of Newtown-on-Arrowsic was rebuilt in 1714 on the southern end of Arrowsic Island, which was incorporated in 1716 by the Massachusetts General Court as Georgetown-on-Arrowsic, named for King George I. The town's boundaries were extended to encompass Parker's Island, Woolwich, Phippsburg and Bath (which included West Bath). Abandoned during Dummer's War and beleaguered during the French and Indian Wars, the region resettled slowly in the 1750s until peace was assured with the 1759 Fall of Quebec.
About half of Parker's Island provided grazing land, and some residents raised livestock and produced butter and cheese. In 1858, there were 2 sawmills, 2 shingle mills, a pailmaker and a shipbuilder. But the merchant marine and fishing were the town's principal occupations. By 1841, all the other parts of Georgetown had been set off and incorporated as towns, leaving Parker's Island with sole claim to the ancient name. Situated between the mouths of the Sheepscot and Kennebec rivers on the Gulf of Maine, Georgetown developed into a summer resort, attracting a number of prominent artists. The island is a noted site for bird watching.
It is crossed by Maine State Route 127. The island is separated by water from Westport to the northeast, Southport to the east, Phippsburg to the west, Arrowsic to the northwest, and Woolwich to the north.
There were 441 households out of which 24.9% had children under the age of 18 living with them, 57.1% were married couples living together, 5.7% had a female householder with no husband present, and 34.9% were non-families. 27.7% of all households were made up of individuals and 9.8% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.84.
In the town the population was spread out with 21.3% under the age of 18, 6.7% from 18 to 24, 26.3% from 25 to 44, 29.4% from 45 to 64, and 16.4% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 94.7 males. For every 100 females age 18 and over, there were 97.3 males.
The median income for a household in the town was $47,813, and the median income for a family was $58,438. Males had a median income of $39,028 versus $24,792 for females. The per capita income for the town was $24,709. About 3.9% of families and 6.8% of the population were below the poverty line, including 5.0% of those under age 18 and 5.2% of those age 65 or over.