Have you tried to google "Craigslist", instead of just typing it into the browser bar?

I generally use Google to bring up Craigslist, and it comes up no problem.  It will typically bring up a city close to me - which probably goes back to which craigslist sites that I use. 

I just clicked on the Craigslist logo, and this is the address it showed:   http://www.craigslist.org/about/sites