Smaller campus offices, College Park employers, and many internship sites -- list their openings in Careers4Terps.
Larger campus offices will have their own personnel and hiring offices, e.g., Department of Resident Life, Department of Transportation Services (including Shuttle-UM), Dining Services, Stamp Student Union, University Libraries, University Recreation and Wellness (including the Outdoor Recreation Center), etc. A short Google search will get you where you're going!
Academic Achievement Programs
Office of Multi-Ethnic Student Education (OMSE)