If you have ever developed an application where users can enter US addresses, then you have probably implemented a state control. Maybe it was just a text field, or maybe it was a drop down list with 50 options. If you're a really smart cookie, it could have 57 to include US territories.
Now, say you want to start supporting Canadian and United Kingdom regions. You might think this would be as easy as finding a list of regions for the country online, and pumping them into the control. Canada lures you into a false sense of confidence. They have ten provinces. That's a nice round number, eh?
At this point your thinking the UK will be a slam dunk. All you have to do is find THE list of UK counties. Easy, right? RIGHT?
Let's make this an interactive blog post. Go ahead and Google for a UK county list. I'll wait. Ok, that wasn't so hard, was it? Now, go find another one. I have all day.
Ok, now compare the two lists you found. Invariably, they will differ by at least 20%. Must be an anomaly in one of the sources, right? Go find a few more. I DEFY you to find two lists that are the same.
Now, what the hell, I ask you? Canada gift wraps ten easy to remember regions. Even the US bungled its way into a nice big round STATIC number. Are you telling me that the UK can't even decide how many regions it has, and what they are called? What, 208 years wasn't long enough?
Settle down you. It's actually kind of complicated. You see, historical bureaucratic cock ups (I should write about the UK more often) have left no less than four legacy county lists in various degrees of relevance. You have your administrative and ceremonial counties. Then you have your traditional counties, complete with nutjobs trying to "save their shires". Dude, we're trying to have a civilization here. Then you have your ISO standard list of UK counties.
Ok, here is the kicker. Even the UK has given up on their own county system. In 1996, they officially converted to postcodes. Basically, every gas station, residence, warehouse, farmhouse, henhouse, outhouse and doghouse  in the UK now has what amounts to a serial number. Screw shires, now you're just a number. Maybe someday we will have administrative, ceremonial and traditional postcodes. I can't wait.
So, what list do you put in your widget? I have no idea. Just take some random cross section of all your results put together. Hey, at least no one can say it's not the official list!