Hey, don't know what the confusion is about, it says underneath the first set of examples the rule.
Here is the rule to express in or to:
- You use en with feminine regions/states/counties (usually ending in -e)
- You use dans le with masculine regions/states/counties starting with a consonant or aspirated h.
- You use dans l' with masculine regions/states/counties starting with a vowel or mute h.
