On behalf of the Department of Homeland Security (DHS), the Student and Exchange Visitor Program (SEVP) manages schools, nonimmigrant students in the F and M visa classifications, and their dependents using the the Student and Exchange Visitor Information System (SEVIS).
SEVP requires every school it certifies to have a principal designated school official (PDSO). Each school may also have additional designated school officials (DSOs) to provide support to F and M students.
Immigration and Customs Enforcement (ICE) is a division of the Department of Homeland Security. You will probably interact with ICE officials as you enter and exit the US.
United States Customs and Immigration Services (USCIS) is another division of the Department of Homeland security. You will probably interact with USCIS officials if you are interested in changing to immigrant status.
A great resource with all the official, government-sanctioned information you need as an international student. If you are looking for answers you can't find on our little guide, look here first.
A source for information on SEVP itself, more specific to interacting with this particular branch of the DHS.
Designated School Officials