In 1999, six graduates from Yale University began going into underfunded and understaffed public high schools in New Haven, Connecticut to teach health workshops. The founding members of this New Haven group, (which now reaches ten New Haven public schools with over 100 volunteers) established Peer Health Exchange, Inc in 2003. They brought their program to New York City first, training over 150 volunteers from Barnard College, Columbia University, and New York University and reaching 1300 low-income high school students that would otherwise have not received any health education in school. In 2006, PHE launched a program in Boston, training college students from Boston University and Harvard College. In the 2006–2007 school year, PHE trained over 270 volunteers in Boston and New York City and reached 1,600 high school students. The program has also been extended into Chicago, Illinois, training college students from DePaul University, University of Chicago, Northwestern University, and University of Illinois Chicago Campus. And to further its impact, in July 2007 PHE initiated a five-year growth plan to deepen impact in current cities and spread throughout the country to new sites, including Mills College, University of Southern California, California State University Northridge, St. Mary's College of California, and University of California, Berkeley. In 2018, the biggest site is New York City reaching high schools in all five boroughs and long standing college chapters include CUNY schools such as Hunter College, City College, Brooklyn College, Queens College, LaGuardia Community College, York College, and College of Staten Island.