Marketo populates a known record with inferred state information leveraging the IP address when a person fills out a Marketo form. Here is an interesting article about what's behind your IP address.

 

The Inferred State Region value for US states and Canadian provinces is abbreviated.

 

Example

 

Inferred State Region values for other countries are often city states.

 

Example

 

Resources

 

Part II - Instructions to Populate State with Inferred State Information.