A group is closing out its public comment period on a push to get an ancient southwestern Illinois historical site designated as a national park. The Belleville News-Democrat reports the Heartlands Conservancy will hold its last public hearing on March 19th at the Cahokia Mounds Interpretive Center. Those behind the push believe that by seeking national recognition, Cahokia Mounds could bring additional regional tourism, jobs and money. The conservancy has been working for more than a year with Native American tribes, government agencies and nonprofits on a feasibility study. Cahokia is believed to have been inhabited from 700 to 1400 A.D., and it was among the most complex societies of prehistoric North America. The 2,200-acre property is designated by the United Nations as a World Heritage Site.