As a result of the September 11, 2001 attacks, the United States began implementing a range of measures to increase the security of its borders and its identity documents.

One result of this was the Western Hemisphere Travel Initiative (WHTI), which mandates as of 2007 that a smaller, more secure number of documents verifying both identity and citizenship be used to facilitate identification and international border crossing.

As a result of the WHTI, U.S. citizens traveling to Canada would have been required to obtain a passport booklet in order to enter the United States.

In order to offer a less expensive and more portable alternative to border communities and frequent travelers, the passport card was developed.

In an effort to improve efficiency at land crossings, the passport card also includes a vicinity-read radio frequency identification chip with a unique identifying number tied to government databases.

[9] U.S. passport cards can be used to enter the United States at land border crossings and sea ports of entry.

The Department of State stated that this limited validity is because "designing a card format passport for wide use, including by air travelers, would inadvertently undercut the broad based international effort to strengthen civil aviation security and travel document specifications to address the post 9/11 threat environment".

[17] Under the REAL ID Act, the passport card is accepted for federal purposes (such as domestic air travel or entering federal buildings), which may make it an attractive option for people whose driver's licenses and ID cards are not REAL ID-compliant when those requirements go into effect on May 7, 2025.

[18] TSA regulations list the passport card as an acceptable identity document at airport security checkpoints.

[20] The passport card is considered a "List A" document that may be presented by newly hired employees during the employment eligibility verification process to show work authorized status.

[23] In some countries, laws require foreign visitors and/or all adults to carry official personal identification at all times.

[citation needed] In addition to the embedded RFID chip, the front of the card features a complex multi-layer hologram consisting of an American bald eagle surrounded by the words "United States of America Department of State" in a small clearly readable font, further surrounded by the same words repeatedly in microprint.

[citation needed] On the rear of the card, the "PASSsystem" mark appears in optically variable ink, and the number C######## is a raised tactile engraving.