http://www.economist.com/news/christmas/21568592-day-economic-life-africas-biggest-shanty-town-boomtown-slum
A not-too-bad story about a town without government (or so the author claims).
http://www.kibera.org.uk/Facts.html
it says the government owns the land, so if that is correct there is a government there.
http://economistsview.typepad.com/economistsview/2012/06/kenyas-kibera-slum.html
this article also talks of government
There is government all around. Some agency is regulating who these folks can interace with outside of the area. Otherwise a place like this would attract lots of foreign capital as investors would be hungry to get all of that entrepreneurial minded labor.