Shapes Who Enters
The categories and caps Congress sets determine how many people can come, from which countries, and for what reasons, affecting families, workers and humanitarian arrivals.
In plain English
It's the set of official ways people can move to the U.S. and stay legally, each with its own rules and yearly limits.
Simple example
In fiscal year 2023, the U.S. issued more than 1 million green cards, with the largest share going to immediate relatives of U.S. citizens, according to Department of Homeland Security data.
Why it matters
What the term actually changes.
Drives Policy Debate
Debates over whether to make immigration stricter or more open often center on adjusting these existing legal pathways and their numerical limits.
How it works
The mechanics, in practice.
Set By Statute
Congress writes the laws that define visa categories, eligibility and annual caps, while agencies like USCIS and the State Department process applications.
Category-Based Limits
Each pathway has its own rules: family and employment visas have per-country and worldwide caps, refugees face an annual ceiling set by the president, and the diversity lottery awards 55,000 visas a year.