Ways to handle state/province UI for different countries

Question

What are some ways to handle UI for Countries, States/Province and zipcode?

When a user selects US we display a "state" dropdown. What are some ways to handle non-US states/provinces and zipcodes?

Should we show an "Other Country" in the state/province dropdown and add a texbox for the user to enter their province if it's not a US one?

Should we just display a text box instead of a dropdown if a non US country is selected?

Should we find a list of provinces/states for each country and populate the dropdown based on Country? For countries with no provinces I guess we would hide the dropdown? I guess we might also have to keep an "Other" since I can't imagine provinces for all countries stay constant forever. It seems it would be difficult to maintain.

Thinking about which way might be good from a programming/maintenance perspective, but also which way would be good from a UI design perspective.

Update: Province/State would be optional for countries other than US.

Answer 1

Make it optional unless you really need to know; some countries have provinces, but they are seldom used, not required in an address, and basically redundant.

Answer 2

I am not a UI-designer, but I am a non-US resident who has to deal with this type of form...

I would suggest that you have a pair of Province/State fields, one a drop-down containing the US values, and the other an optional text field. Arrange for them to be displayed in the same place on the form and hide whichever one is not relevant for the Country selection. I wouldn't complain too much if your form defaulted to Country=US and the drop-down visible.

(There's a subsidiary question of what to call the non-US version of the field - "Province/State" is not necessarily a term used in every country. In the UK, for instance, we'd normally call it "County". However, I'd suspect that "Province/State" would be sufficiently widely understood as not to be a problem.)