Since 1996, goose Guangdong lineage H5 highly pathogenic influenza A viruses (HPIAV) have caused a panzootic with significant impacts on poultry and wild birds. In December 2021, subclade 2.3.4.4b H5N1 HPIAV spread throughout North America, where atypical detections of fatal H5N1 HPIAV infections have been recorded in wild mammals. The goal of this study is to determine the seroprevalence of H5N1 IAV in wild canids in Pennsylvania before and after HPIAV introduction.