Massachusetts COVID-19 Data
I have been cataloging the daily case reports from the Commonwealth of Massachusetts to serve as a record of these daily updates. The source URL for this data is https://mass.gov/info-details/covid-19-cases-quarantine-and-monitoring.
I have all of the PDFs starting from March 9, 2020, which I believe to be the first date that the government published this sort of report.
In addition to the daily case report PDFs, I have been manually assembling CSVs of cases, deaths, and tests by day. These are also linked on this page.