How do I determine which consulate to apply through for a multiple country trip to the Schengen Region?

When applying for a Schengen visa for a trip involving multiple Schengen countries, you must apply through the consulate of the main country you'll be visiting in the itinerary of your trip. The main country is either the country of your longest stay or the country of your first point of entry.

-Longest Stay: If you will be spending a longer amount of time in one country over others, apply to the consulate of the country where you will stay the longest in terms of number of days.

-First Point of Entry : If the number of days is equal in all countries, then apply at the consulate of the country you will enter first.