USState provides a select box of US state names. The full name is displayed, while the two-letter code is used as the field's value.
USState
The plain preset:
<cf_terrafield preset="usstate" name="MyState1" />
Set Virginia as the default and make it a required field:
<cf_terrafield name="MyState2" caption="state (2)" preset="usstate" default="VA" required="true" />
Use checkboxes to allow multiple selections:
<cf_terrafield name="MyStates3" preset="usstate" caption="states (3)" format="checkbox" cols="3" />
Fields marked with * are required.