A girl from Philadelphia asked me about starting to model there. In Philadelphia, PA, it seems to be mostly about working with casting agencies and talent agencies.
Once you have a headshot or modeling compcard ready, you can mail these agencies y postal mail.
There are others but these are good places to start.
Again even though I am sharing the websites, Do NOT submit through email, electronically, it is more professional to POSTAL MAIL your photos. Always is.