The US DHS has announced the list of airports through which Americans who have visited any Schengen Zone country, the UK or Ireland in the 14 days prior to their scheduled arrival in the US must re-enter the country:
Furthermore:
"Upon arrival, travelers will proceed to standard customs processing. They will then continue to an enhanced entry screening where the passenger will be asked about their medical history, current condition, and asked for contact information for local health authorities. Additionally, some passengers will have their temperature taken.
"After the enhanced entry screening is complete, passengers will be given written guidance about COVID-19 and be allowed to proceed to their final destination.
"Once home, individuals must immediately self-quarantine in their home and monitor their health in accordance with CDC best practices."