Marriage of American citizens in Hungary must be performed in accordance with Hungarian law. A marriage that is valid under Hungarian law is generally valid in any state of the United States. If you wish to get married in Hungary, contact the district office of the town in which you, or your spouse-to-be, is a resident or the nearest Hungarian Consulate in the United States to ascertain the local marriage requirements.
An American citizen who wants to get married in Hungary must establish to the satisfaction of the Hungarian authorities that s/he is free to marry under the laws of the state of his/her residence in the United States. Hungarian authorities have generally accepted affidavits of civil status - Tanusítvány. This document can be obtained through ACS for 30 USD or HUF equivalent.
Be prepared to present an original birth certificate, any previous divorce decrees, and any other relevant documents needed to get married. Non-Hungarian documents must be presented to Hungarian authorities with certified Hungarian translations. To be legal, all marriages must be performed by a Hungarian civil authority. Religious ceremonies do not have legal validity under Hungarian law.