Overview#Nonimmigrant Information System (NIIS) is a Government Data Store Operated by the United States Customs and Border Protection and the primary source of data on nonimmigrant admissions into the United States.
Nonimmigrant Information System compiles and maintains information collected from nonimmigrants by United States Department of Homeland Security (DHS) Form I-94, also known as the Arrival-Departure Record, which asks for dates of arrival and departure as well as limited demographic information, such as name, gender, nationality, and Date Of Birth.
Each time a nonimmigrant enters the United States, the arrival portion of the I-94 Form is collected and the information is entered into the data system. Conversely, each time a nonimmigrant leaves the United States, the departure portion is collected and the additional information is entered into NIIS. The arrival and departure records are then electronically matched, producing a single record that includes both the arrival and departure date.
Nonimmigrants arriving by air, land, or sea are required to complete Form I-94 with two important exceptions. Canadians who travel to the United States as tourists or on business generally do not need the I-94 Form. Also, certain Mexicans who have a nonresident alien Border Crossing Card, commonly known as a laser visa, may not require the I-94.