It also has Rutgers New Brunswick and Princeton.
Princeton's actually in Mercer County.
I grew up there. It's become incredibly more diverse in the last 20-30 years, like California, with a very large South Asian and East Asian population. Even before then it had a large Jewish and Eastern European population as well as small, struggling cities like New Brunswick, Perth Amboy, and South Plainfield. It had few upscale suburbs like you see in Bergen, Morris, or Somerset... its suburbs went up quickly on farmland, orchards, and swamps, solidly middle class and not fancy. When the Verrazano Bridge opened in the 1960s this was the closest part of NJ to people leaving Brooklyn; most of my classmates' parents were from Brooklyn or Statem Island. The Republicans' religious right turn in the '90s did not play well here.