COVID-19: Federal Travel Restrictions and Quarantine Measures [Updated May 28, 2020] [open pdf - 658KB]
From the Document:"In response to the ongoing Coronavirus Disease 2019 (COVID-19) pandemic, the federal government has taken several actions to deter persons with potential COVID-19 infection from entering the country. This Legal Sidebar examines the legal authorities underlying two categories of these actions: First, restrictions on the entry of many non-U.S. nationals (aliens) who recently have been physically present in mainland China, Iran, much of Europe, and Brazil; and second, quarantine requirements imposed on all persons entering the United States, regardless of citizenship status. A separate Sidebar discusses additional actions the federal government has taken to restrict the movement of foreign nationals through ports of entry on the land borders with Canada and Mexico."
CRS Legal Sidebar, LSB10415
Congressional Research Service: https://crsreports.congress.gov/