A southwestern Illinois county is rallying behind a push to get an ancient southwestern Illinois historical site designated as a national park.  The Belleville News-Democrat reports that Saint Clair County’s governing board unanimously approved a resolution calling on Congress to take the action involving Cahokia Mounds east of Saint Louis.  Those behind the effort believe that by seeking national recognition, Cahokia Mounds could bring additional regional tourism, jobs and money.  Cahokia is believed to have been inhabited from 700 to 1400 A.D., and it was among the most complex societies of ancient North America.  The 2,200-acre property is designated by the United Nations as a World Heritage Site.  Monday’s resolution follows similar recommendations by Governor Pat Quinn and the Illinois Historic Preservation Agency.