It depends on the employer. Smaller businesses are less likely to have other students, but they offer a great opportunity to learn a lot about the enterprise. Many larger companies employ multiple students each term. Regardless of whether or not there are other students there, good college programs approve work positions that will provide productive tasks and supervision for students. You will talk with your co-op coordinator to help you decide.
Colleges have information on work sites in a variety of locations.
If you are thinking about a more distant location, they can often help with information about places students have worked before. Some employers assist with the travel and living arrangements for distant locations. Or, you may be put in touch with other students who will be living and working in the area. Explore it with your co-op office. Many co-op students find the salary they earn is a great benefit.