It was created in 2005 when PIHA expanded west with five teams in Colorado. PIHA aligned its teams into two conferences. PIHA again expanded in 2006 into the St. Louis and New England areas, and realigned each conference was divided into two divisions. When the league contracted prior to 2009, it combined the its divisions into the current Atlantic Division. The Eastern Conference Championship Trophy is awarded annually to the conference champion.
Prior to the 2005 expansion and realignment, the Eastern Conference had only the Eastern Division. After the 2006 expansion the Eastern Conference was divided into two divisions: the Northeast and Mason Dixon. For the 2008 expansion, the Eastern Conference added two more divisions: the Atlantic and Southeast, bringing the division total to four. The league then contracted in 2009, which dissolved all divisions in the East except for the Atlantic Division.