Keep Families Together Act This bill limits the separation of families at or near U.S borders or ports of entry and imposes limits on the prosecution of asylum seekers. The Department of Homeland Security (DHS), Department of Justice (DOJ), and Department of Health and Human Services (HHS) shall not separate a child from a legal guardian at a port of entry or within 100 miles of a U.S. border unless a state court terminates the legal guardian's rights; a state child welfare agency or court determines it is in the child's best interests to be removed; or the child is determined to be a trafficking victim or at risk of becoming one, the accompanying adult is most likely not the legal guardian, or the child is in danger of abuse or neglect. Such separation shall end unless a licensed independent child welfare expert authorizes the separation within 48 hours. DHS, DOJ, or HHS may not separate a child from a legal guardian solely to deter migration into the United States or to promote compliance with immigration laws. DHS shall develop (1) training related to the bill's family separation requirements, and (2) guidance for how legal guardians may locate a separated child. HHS shall provide legal guardians weekly status updates about a separated child. An asylum seeker who has expressed a credible or reasonable fear of persecution may not be prosecuted for certain immigration law violations until the asylum application has been finally adjudicated.