Peterborough's population is composed of a wide range of ethnic groups. It is predominantly white, with 11.6% black residents and a small percentage of American Indian and Alaska Natives. The city also has a significant Asian community, with populations of 3.0% Vietnamese, 0.9% Chinese, and 0.8% Asian Indian. Additionally, there is a significant Hispanic population in Peterborough. As of 2010, Hispanics made up 20.9% of the city's population, including 12.7% Puerto Rican residents. The city is also home to a large number of Aboriginal communities.
According to the 2010 census, the population of Peterborough was eighty-one thousand and eighty-five in number. That makes the city's median age of thirty-two years old the fifth oldest in the state. The majority of the population is between the ages of 15-64, although an estimated one-fourth of the population is over 85 years old.
Peterborough's diverse economy includes several different industries, including financial services, light industry, and digital media. Its geographic location makes it a prime location for warehousing and logistics firms. The city is also only 70 miles from the capital, making it easy to travel by train.
In the early nineteenth century, Peterborough's economy transitioned into manufacturing. Textile, shoe, and clothing factories were established along the Blackstone River. The Peterborough and Boston Railroad opened in 1835, and the town became an important transportation hub. The city's population grew rapidly throughout the 19th century. In 1851, it was home to 9,000 people, and it reached seventeen thousand by 1871.