Protecting UACs Through Enhanced Sponsor Vetting Act of 2017 This bill establishes additional sponsor vetting requirements for placement of unaccompanied alien children (UACs) who are in federal custody because of their immigration status. UACs are children under the age of 18 with no lawful immigration status who either have no parent or legal guardian in the United States, or have no parent or legal guardian in the United States available to provide care and physical custody. The Homeland Security Act of 2002 is amended to require the Department of Health and Human Service's Office of Refugee Resettlement, as part of its UAC placement determinations, to: notify the governor and the chief executive of the county in which a sponsor resides of a prospective placement; include the Federal Bureau of Investigation and state and local law enforcement officials in consultations regarding UAC adherence to hearing requirements and safety from criminal or exploitive elements, including protection from members of a transnational criminal organization. Prior to making a placement determination the office shall: coordinate with the Department of Justice to use the Next Generation Identification System to check the criminal background of prospective sponsors; and consult with federal, state, and local law enforcement entities. The office shall also: notify state and local governments of a placement determination, including notifying the governor and mayor of the locality in which the sponsor resides; and provide the Terrorist Screening Center with any information uncovered during the placement process that establishes the child's or sponsor's membership or affiliation with a transnational criminal organization.