US citizens do not require a visa for stay of 90 days or less for business and tourist trips; if you plan to stay longer than 90 days, in most cases you can extend your visa 1 time while in the Turks and Caicos.  Your passport must be valid at the time of entry, and there is no rule regarding any number of blank visa pages in your passport. For recent travel requirement changes and more detailed information, please refer to the State Department website.