I would probably say that the majority are emigrating for the same reason as many other countries first and foremost - economic problems and violence.
Surprisingly Elizabeth and North jersey in general is one of the largest landing locations for Colombian emigrants next to South Florida. Morris Ave in specific in Elizabeth is a ‘Little Colombia’ in some respects, as there are 15+ Colombian restaurants, shops, cafes etc.
I was visiting family in Port St. Lucie not long ago and I came across a Colombian bakery/luncheonette. I talked to the owner and found out he moved from Elizabeth.
On that note, I stopped by a new place in the Elmora neighborhood today, called Colombian Coffee Shop, which serves as a small bakery and cafe. Grabbed a coffee and a pandebono for $2.25.
