Do US citizens need a Visa to travel to India?

Yes. The following info is from the US Department of State ( http://www.travel.state.gov/travel/cis_pa_tw/cis/cis_1139.html ) ENTRY/EXIT REQUIREMENTS: U.S. citizens require a valid passport and valid Indian visa to enter and exit India for any purpose. Visitors, including those on official U.S. government business, must obtain visas at an Indian Embassy or Consulate abroad prior to entering the country, as there are no provisions for visas upon arrival. Those arriving without a valid passport and valid visa are subject to immediate deportation. The U.S. Embassy and Consulates in India are unable to assist when U.S. citizens arrive without proper documentation. Each visitor should carry photocopies of the bio-data page of the traveler's U.S. passport and the page containing the Indian visa in order to facilitate obtaining an exit visa from the Indian government in the event of theft or loss of the passport. Replacing a lost visa in order to exit the country takes up to three business days.

Americans wishing to visit India are responsible for requesting the correct type of visa from the Indian Embassy or Consulate, as there generally are no provisions for changing one's immigration category (e.g., from tourist to work visa) once admitted. As of October 1, 2007, the Indian Embassy and Consulates in the U.S. outsourced the visa application process to Travisa Visa Outsourcing: http://indiavisa.travisaoutsourcing.com. Diplomatic and Official visa applications, however, are still accepted directly at the Indian Embassy and Consulates. Foreign citizens whose primary purpose of travel is to participate in religious activities should obtain a missionary visa rather than a tourist visa. Indian immigration authorities have deported American citizens who entered India with a tourist visa and conducted religious activities. American travelers to India who work in "designated institutes and technology areas" will be subject to a two week waiting period in the visa application process and will be required to submit supplemental information with their visa application. Scholars planning to conduct research in India often need research clearances in addition to their visas. Specific information is available at the Indian Embassy and Consulates.