Greencastle is a very small borough located in the state of Pennsylvania. With a population of 4,224 people and three associated neighborhoods, Greencastle is the 360th largest community in Pennsylvania.

Also of interest is that Greencastle 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: 9.63% 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.

Being a small borough, Greencastle does not have a public transit system used by locals to get to and from work.

The education level of Greencastle citizens is substantially higher than the typical US community, as 29.46% of adults in Greencastle have at least a bachelor's degree.

The per capita income in Greencastle in 2022 was $44,613, which is wealthy relative to Pennsylvania and the nation. This equates to an annual income of $178,452 for a family of four. However, Greencastle contains both very wealthy and poor people as well.

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

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