<ACCESSION-NUMBER>0001193125-11-301684 <TYPE>10-Q <PUBLIC-DOCUMENT-COUNT>21 <PERIOD>20110930 <FILING-DATE>20111108 <DATE-OF-FILING-DATE-CHANGE>20111108 <FILER> <COMPANY-DATA> <CONFORMED-NAME>HANOVER INSURANCE GROUP, INC. <CIK>0000944695 <ASSIGNED-SIC>6331 <IRS-NUMBER>043263626 <STATE-OF-INCORPORATION>DE <FISCAL-YEAR-END>1231 </COMPANY-DATA> <FILING-VALUES> <FORM-TYPE>10-Q <ACT>34 <FILE-NUMBER>001-13754 <FILM-NUMBER>111187089 </FILING-VALUES> <BUSINESS-ADDRESS> <STREET1>440 LINCOLN ST <CITY>WORCESTER <STATE>MA <ZIP>01653 <PHONE>5088551000 </BUSINESS-ADDRESS> <MAIL-ADDRESS> <STREET1>440 LINCOLN ST <CITY>WORCESTER <STATE>MA <ZIP>01653 </MAIL-ADDRESS> <FORMER-COMPANY> <FORMER-CONFORMED-NAME>ALLMERICA FINANCIAL CORP <DATE-CHANGED>19950501 </FORMER-COMPANY> </FILER>