You can transfer from anywhere, USC is a private school and doesn’t give priority to instate students. 4 year, 2 year, anywhere in US or international, although they do have some schools they seem to accept more transfers from. There are many transfers threads to start getting data from and likely to get responses from experienced transfer students. Here is one:
http://talk.collegeconfidential.com/transfer-students/1801383-2016-2017-usc-transfer.html
Good Luck!