You can get the information about Archives' open status under the influence of COVID-19 below.
7/28/2021 update
【United States of America】
・National Archives and Records Administration
https://www.archives.gov/coronavirus
National Archives Announces Limited Reopening of Research Rooms(2021/7/16)
https://www.archives.gov/press/press-releases/2021/nr21-50
Facility Information
https://www.archives.gov/college-park
・Library of Congress
For Piblic
https://www.loc.gov/about/pandemic-information/for-public/
For Researchers
https://www.loc.gov/about/pandemic-information/for-researchers/
・Gordon W. Prange Collection (University of Maryland)
https://www.lib.umd.edu/about/coronavirus-updates
COVID-19 Information for UMD