One of these services is the riverboat gaming industry. The conglomerate cities in the 'Quad' are:Įven though citizens of the region hail from two different states, they share many resources and services. With recent new developments, that trend is changing. Gambling in this area is legal, but up until now has taken place primarily on riverboats. The name 'Quad Cities' resonated better with natives, however, and remains so today. As the mecca evolved into four areas, then five, the people discussed re-naming the area the Quint Cities. The conglomerate exists along the Mississippi River and began as a group of only three towns, the Tri Cities. In the heart of the United States lie the Quad Cities, a five-city conglomerate stretching across Iowa and Illinois.