The links below will direct you to resources at the Pitt Archives on particular religious and ethnic groups in Pittsburgh. As Dr. Musekamp suggests, you can also start your search in Historic Pittsburgh.
Social Explorer has historical Census data which can help you find out the ethnic and racial makeup of Pittsburgh over the years. Please contact Chris Lemery if you need assistance using this resource.
Below are some of the major Pittsburgh newspapers. You may also want to take a look at our Pittsburgh & Regional Newspaper Guide for newspapers published by various ethnic groups in the city.