The borough was settled about 1760 and first incorporated in 1875. Slate quarries pepper the area, but only a few are still functioning.
The founder and first Chief Burgess of Bangor was Robert M. Jones, an emigree from Bangor, Wales. He was the prime mover in the establishment of the slate industry in Northampton County. A life-sized statue of him, dedicated on September 24, 1914, remains in the town center. In the official program for the unveiling it states "... Mr. Jones in his prime had many charming qualities, chief among which was his constant optimistic disposition."
Indeed, if one visits Bangor, Wales it is clearly visible that the Welsh heritage made its way to Bangor, Pennsylvania. The stone walls, rectangular gardens, and lovely flowers and greenery of Wales mirror that of Bangor, Pennsylvania. Around Bangor one can also see the piles of slate residue and shale that is reminiscent of the area around Bethesda, Wales.
As of the census of 2000, there were 5,319 people, 2,105 households, and 1,420 families residing in the borough. The population density was 1,333.6/km² (3,453.4/mi²). There were 2,249 housing units at an average density of 563.9/km² (1,460.2/mi²). The racial makeup of the borough was 97.9% White, 0.5% African American, 0.2% Native American, 0.3% Asian, 0.3% from other races, and 0.8% from two or more races. Hispanic or Latino of any race were 0.8% of the population.
There were 2,105 households out of which 35.2% had children under the age of 18 living with them, 50.4% were married couples living together, 11.8% had a female householder with no male householder present, and 32.5% were non-families. 28.6% of all households were made up of individuals and 14.9% had someone living alone who was 65 years of age or older. The average household size was 2.52 and the average family size was 3.09.
In the borough the population was spread out with 27.7% under the age of 18, 6.9% from 18 to 24, 31.2% from 25 to 44, 17.8% from 45 to 64, and 16.4% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 91.1 males. For every 100 females age 18 and over, there were 86.6 males.
The median income for a household in the borough was $36,382, and the median income for a family was $44,954. Males had a median income of $36,972 versus $21,414 for females. The per capita income for the borough was $17,742. About 8.5% of families and 13.1% of the population were below the poverty line, including 19.0% of those under age 18 and 15.1% of those age 65 or over.