Ancestry Library Edition is a comprehensive online source of information for genealogical research, with billions of names in over 6,000 databases. You can access Ancestry Library Edition at the Round Rock Public Library (library access only).

Search through census records; birth, marriage and death records; immigration records; vital and church records; military records; and court, land and probate records are included. Popular databases include the U.S. Federal Census from 1790 to 1930, Social Security Death Index, Civil War records, U.S. Public Records Index, American Genealogical-Biographical Index and Federal Slave Narratives.

The Round Rock Public Library also houses the collection of the Williamson County Genealogical Society, which focuses on United States genealogy, the Southern states, Texas, and Williamson and surrounding counties.