jQuery Shorten Switch Statement
You can convert it to two array. The first will normalize multiple "aliases" of the same key into one and second will have your address values.

var aliases = {
  "hyde" : "hydepark",
  "uofc" : "hydepark",
  "uchicago" : "hydepark",
  "wttw" : "willis"
};

var addresses = {
  "hydepark" : "5801 South Ellis Avenue, Chicago, IL",
  ...
};

var alias = aliases[xstreets[2]];
if(alias == undefined) {
  alias = xstreets[2]
}
var address = addresses[alias];
if(address == undefined) {
  return xstreets[0]+" &amp; "+xstreets[1]+" Chicago IL";
}
return address;