We have previously written about the abundance of acronyms that are used by US immigration attorneys. At our office, some of those acronyms we use most frequently include: USCIS, CBP, DHS, DOS, and DOL, all of which happen to be five of the most important federal agencies involved in US immigration. (Immigration & Customs Enforcement—i.e., ICE—also has a large impact on some US immigrants, but our firm does not often work with this agency.) In this post, we provide a brief introduction to five of the federal agencies we work with most often, explain their areas of oversight, and how they are related.