Yes, you're right in that most websites seem to suggest the Freedom of Information Requests for foreign citizens.

However, US citizens can indeed do this.

[Chris Guillebeau documents his process of doing this](https://chrisguillebeau.com/foia-request-for-travel-history/) and he's a US citizen (who has visited every country in the world).

He got back from his request:

>  - A letter with an official response from the U.S. Customs and Border Protection
>  - A long list (14 pages) of my international arrivals and departures
>  - Another long list (8 pages) of various flight data, discussed below