En/au/aux = In/to with countries and continents (French Prepositions)

In French, to express in/to + [country], you can use en / au / aux  depending on the gender of the country.

Learn how to say "in/to a country" in French

We know that countries and continents have genders in French [see Continents/countries/counties/regions/states are masculine, feminine or plural in French (Gender)]

Note that while we always use in and to in English for cities and countries, in French we use different prepositions for one or the other.
We use à with cities À = To/in and De = From/of with cities in French (French Prepositions of Location), it's a bit more complicated when it comes to countries.

Have a look at these examples:

Here are the rules:

ATTENTION: 

For pronunciation reasons, you will use en with masculine countries starting with a vowel:

Note that Le Québec behaves like a country, even though it's a province:

See also the related lesson: En/Dans = in/to + regions/states/counties (French Prepositions)