Several outlets have developed background materials for understanding the factors that have led to the current crisis of refugees/migrants on the border from Central America.
The first link is a blog post from an immigration lawyer detailing the hurdles lawyers face in trying to represent families in detention centers:
The Artesia Experience
The Wilson Quarterly has put together an interactive set of maps and graphs which detail the underlying factors which lead people to leave places like Honduras and El Salvador:
Wilson Quarterly Interactive Map
Huff Post Latino Voices has also examined the U.S. influences that have helped lead to the current crisis:
Here's How The U.S. Sparked A Refugee Crisis On The Border, In 8 Simple Steps
Protests against the influx were set for this weekend, although turn-outs tended to be small, it is an illustration of the divides in public opinion created by the crisis: