The Federal Register compiles a wealth of useful information including public notices of hearings, investigations, grants, etc.; text of proposed rules and regulations of the various administrative agencies; text of final rules prior to codication in the CFR; and presidential documents (i.e., executive orders, proclamations, etc.).
Code of Federal Regulations (CFR)
The Code of Federal Regulations (CFR) annual edition is the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. It is divided into 50 titles that represent broad areas subject to Federal regulation. Title 8 specifically applies to Aliens and Nationality, although you may find provisions in other titles.