These may help.....
U.S. Embassies and Consulates routinely do not accept applications for "E" visas from third country national applicants who are not resident in their consular districts.
VWP travelers who have been admitted under the Visa Waiver Program and who make a short trip to Canada, Mexico or an adjacent island generally can be readmitted to the United States under the VWP for the balance of their original admission period. See the Department of Homeland Security’s Customs and Border Protection (CBP) website for additional details. Also VWP nationals resident in Mexico, Canada or adjacent islands are generally exempted from requirements to show onward travel to other foreign destinations. Learn more at the CBP website.
http://travel.state.gov/visa/temp/without/without_1990.html
https://help.cbp.gov/app/answers/detail/a_id/194/~/visa-waiver-program---eligible-countries
While in the U.S., you may go to Canada, Mexico and the Caribbean and re-enter the U.S. using the I-94W you were issued when you first arrived in the U.S., although the time you spend there is included in the 90 days allotted for your visit.
If you go to Canada and Mexico or the Caribbean, and while you are there, your initial 90-day period of entry expires, but you need to come back in to the U.S. to fly home, you may encounter a problem. The terms of the VWP are very clear - it is only to be used for occasional, short visits to the U.S. If the CBP Officer thinks you are trying to "reset" the clock by making a short trip out of the U.S. and re-entering for another 90-day period, you can be denied entry. (If that happens, you will have to obtain a visa for any future travel to the U.S.) In order to be re-admitted to the U.S. shortly after a previous admission expired, you will have to convince a CBP Officer that you are not trying to "game" the system.
If you are coming under the VWP, you must apply in advance for an Electronic System Travel Authorization. We recommend you apply at least 72 hours in advance of your travel, but emergency, last minute travel can usually be accommodated.
If you visit other countries such as England or Costa Rica, then return to the U.S., your re-entry will be considered to be a new admission (thereby restarting the 90 day clock), rather than a re-entry from a contiguous country in the course of your initial visit, and the admission inspection may be more strenuous. The Officer inspecting you will want evidence that you intend to go back home to your country of citizenship to live as opposed to returning again and again to the U.S. after visits to other countries.
If you are from Canada, the length of stay for tourism is 6 months. Canadians may file for an extension of stay with the U.S. Citizenship and Immigration Services.
If you are not from a visa waiver country, you will need a visa.
