US citizens travelling to India require a visa to be obtained from Indian consular office. The US passport is required to have a minimum validity of six (06) months and the least 2 blank pages for visa stamp.
More statutory details are available at the following federal pages.
Pre departure Travel guidelines for US Citizens from Government of USA:
Guidelines on arrival from Govt. of India for International visitors’
A) https://indianvisaonline.gov.in/evisa/tvoa.html
B) https://boi.gov.in/content/general-instructions-registration-foreigners
C) https://boi.gov.in/content/where-register
D) http://keralapolice.gov.in/e-services/foreigners-registration
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