Compact of Free Association Host Communities Support Act This bill authorizes various financial waivers for certain U.S. jurisdictions (i.e., states, territories, or possessions) that host citizens of the Marshall Islands, Micronesia, or Palau as residents. (Under current law, citizens of these countries, known as the Freely Associated States, have the right to reside and work in the United States as nonimmigrants or habitual residents.) Specifically, this bill authorizes a federal agency to, for the purposes of a federal grant, waive any matching funds requirements for a jurisdiction that hosts citizens of the Freely Associated States as residents. Furthermore, the President may reduce, release, or waive amounts that such a hosting jurisdiction owes to a federal agency, at the request of the hosting jurisdiction. As a condition of receiving such a reduction, release, or waiver, a hosting jurisdiction must report to the Department of the Interior an accounting of the jurisdiction's unreimbursed economic impacts associated with receiving citizens of the Freely Associated States from 2004 through 2021.