Data related to state-wide implementation of social-distancing policies were manually curated by web search and independently reviewed by a second author; disagreements were rare and resolved by discussion. Government websites were prioritized as sources of truth where feasible; otherwise, news reports covering state-wide proclamations were used. All citations are captured in the data file. Ground truth data used in the validation were manually curated from states’ Department of Public Health websites. Citations of the validation data are included in the data file. To confirm global accessibility of covidcounties.org, we used dareboost.com to perform loading speed tests from 14 cities across the globe using three different devices: Google Chrome via desktop, iPhone 6s/7/8, and Samsung Galaxy S6.

Management of the COVID-19 pandemic has proven to be a significant challenge to policy makers. This is in large part due to uneven reporting and the absence of open-access visualization tools to present and analyze local trends as well as infer healthcare needs. Here we report the development of CovidCounties.org, an interactive web application that depicts daily disease trends at the level of US counties using time series plots and maps. This application is accompanied by a manually curated dataset that catalogs all major public policy actions made at the state-level, as well as technical validation of the primary data. Finally, the underlying code for the site is also provided as open source, enabling others to validate and learn from this work.