Middlesex is a medium-sized borough located in the state of New Jersey. With a population of 14,461 people and three associated neighborhoods, Middlesex is the 133rd largest community in New Jersey.

Also of interest is that Middlesex has more people living here who work in computers and math than 95% of the places in the US.

Telecommuters are a relatively large percentage of the workforce: 9.11% 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 population of Middlesex is very well educated relative to most cities and towns in the nation, where the average community has 21.84% of its adult population holding a 4-year degree or higher: 34.48% of adults in Middlesex have a bachelor's degree or even advanced degree.

The per capita income in Middlesex in 2022 was $50,637, which is middle income relative to New Jersey, and wealthy relative to the rest of the US. This equates to an annual income of $202,548 for a family of four. However, Middlesex contains both very wealthy and poor people as well.

Middlesex is an extremely ethnically-diverse borough. The people who call Middlesex home describe themselves as belonging to a variety of racial and ethnic groups. The greatest number of Middlesex residents report their race to be White, followed by Asian. Middlesex also has a sizeable Hispanic population (people of Hispanic origin can be of any race). People of Hispanic or Latino origin account for 26.32% of the borough’s residents. Important ancestries of people in Middlesex include Italian, Irish, German, Polish, and English.

Foreign born people are also an important part of Middlesex's cultural character, accounting for 23.73% of the borough’s population.

The most common language spoken in Middlesex is English. Other important languages spoken here include Spanish and Arabic.