As known when people travel to another country a valid travel document (Passport) or valid identity is needed (Except EU countries). As Turkey is still not an EU country the entry regulations are set according the custom and entry regulations Turkey has agreed with each individual country.
U.S. citizens must have a visa to enter Turkey. U.S. citizens may obtain a visa upon entry into Turkey or in prior to departure from one of the five Turkish Consulates in the United States. Please find your state in the Turkish Consulates Jurisdiction List. Business visas must be issued prior to departure by Turkish consular offices.
Visas issued upon entry are valid for three months. Visas for longer stays and for study, research or employment must be obtained in advance. Passengers in transit through Turkey who do not leave their port of transit do not require visas.
Non-U.S citizens must apply for tourist or business visas before traveling to Turkey. Applicants should contact the relevant Turkish Consulate in person, by mail or by a courier service. Applicants outside the united States should contact the nearest Turkish Embassy or Consulate to learn their visa requirements and procedures. Turkish missions abroad are listed at www.mfa.gov.tr