Northumberland is a very small borough located in the state of Pennsylvania. With a population of 3,860 people and two associated neighborhoods, Northumberland is the 401st largest community in Pennsylvania.

Telecommuters are a relatively large percentage of the workforce: 8.17% of people work from home. While this number may seem small overall, as a fraction of the total workforce it is high relative to the nation. These workers are often telecommuters who work in knowledge-based, white-collar professions. For example, Silicon Valley has large numbers of people who telecommute. Other at-home workers may be self-employed people who operate small businesses out of their homes.

The education level of Northumberland citizens is a little higher than the average for US cities and towns: 21.18% of adults in Northumberland have at least a bachelor's degree.

The per capita income in Northumberland in 2018 was $32,355, which is middle income relative to Pennsylvania and the nation. This equates to an annual income of $129,420 for a family of four. However, Northumberland contains both very wealthy and poor people as well.

The people who call Northumberland home describe themselves as belonging to a variety of racial and ethnic groups. The greatest number of Northumberland residents report their race to be White, followed by Black or African-American. Important ancestries of people in Northumberland include German, Irish, English, Polish, and Dutch.

The most common language spoken in Northumberland is English. Other important languages spoken here include Polish and Italian.