The Immigration Act of 1924 was a US law that resulted in the development of a quota system for individuals trying to enter the US.
The US only allowed a certain number of immigrants from each country as a means to control immigration and the type of immigrants received. For example, there were only 165,000 immigrants total allowed in the US during the year. This included 51,227 allowed from Germany, 34,007 from Great Britain and Northern Ireland, and 5,982 from Poland. These are just a few examples of numbers for different countries.