Strictly speaking, RTP[1] is a small area (mostly) in Durham County, NC, where a research park is located, where a lot of major technology and pharma companies, and tons of small companies, have R&D and/or manufacturing operations.

Colloquially, people use "RTP" as shorthand for "The Triangle"[2] which is generally considered an area roughly defined by a triangle of lines connecting Raleigh, Durham and Chapel Hill. Or, depending on your take, connecting Duke University, the University of North Carolina at Chapel Hill, and NC State University.

RTP (or "The Triangle") is a tech hub in the Southeast region, and is becoming quite a startup hotbed. But one of the limitations of this area is lack of access to early stage capital. Of all the things that hurt entrepreneurs in this area, that's probably the single most encountered problem. :-(

[1]: http://en.wikipedia.org/wiki/Research_Triangle_Park

[2]: http://en.wikipedia.org/wiki/Research_Triangle

Research Triangle Park

It's the area where Chapel Hill, Durham, and Raleigh, NC are.