What is the proper salutation to be used in a letter to a consulate?
The highest office in a Consulate is a Consul, the highest
office in a Consulate-General is a Consul General, and the highest
office in an Embassy is an Ambassador.
You would address the letter as:
The Honorable John Smith, Consul
Consulate of "conventional long form of whatever country"
Street address
City, State, zip
In the letter however, the salutation would simply be Dear Mr.,
Mrs., Miss, or Ms., the same goes for a Consul General
A foreign Ambassador would be:
His (or Her) Excellency John Smith
Ambassador of "conventional long form of whatever country"
Street address
City, State, zip
The salutation for an ambassador would be either Excellency, or
Dear Mr. (or Madam) Ambassador