What countries require a state/province in the mailing address?

Question

I'm creating a form and want to require / hide the state/province field based on the selected country. What countries require a state in the mailing address? For example, the United States does.

Answer 1

Not a complete list:

• USA
• Canada
• Australia
• China (PRC)
• Mexico
• Malaysia
• Italy (strictly speaking; we don't collect Italian provinces and I don't think we've ever had a problem with sending mail there)

To the best of my knowledge no other European country requires states/provinces in addresses.

Also see http://www.bitboost.com/ref/international-address-formats.html for more info.

Answer 2

Actually, I'm not sure if it's a postal requirement, but it's common practice here in Spain. Obviously you could find the location via postal code, just like the zip code in the US tells you which state it's in, but every single Spanish-based website requires it.