A data app for exploring official statistics on US immigration enforcement.

Immigration enforcement is one of the most debated topics in American politics — but the public conversation rarely engages with the underlying data. This app makes it easy to explore two key datasets and draw your own conclusions:

  • ICE Detentions — sourced from the Transactional Records Access Clearinghouse (TRAC), this dataset provides periodic snapshots of the detainee population held in ICE facilities, broken down by arresting agency and criminal status. The app fetches the latest data from TRAC on load.
  • Border Patrol Encounters — combines a historic dataset from the Office of Homeland Security Statistics (OHSS) covering October 1999 through November 2024 with monthly updates from Customs and Border Protection (CBP) covering December 2024 onward. Note: the CBP portion requires a manual update step and currently reflects data through August 2025.

Unlike my other projects, this app draws on federal enforcement data rather than Census data — which required different data wrangling: scraping, Excel workbooks, and fiscal year conversions.

Try the app here and explore the code here. This project was featured in Alberto Cairo’s Open Visualization Academy interview series.

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Ari Lamstein

Ari Lamstein

I build open source tools for exploring public data — and teach others to do the same. I teach data app development for O’Reilly and have written tutorials for RealPython.