Before COVID-19, less than 7% of annual American grocery sales took place online. We hypothesize that during the COVID-19 pandemic, shoppers have decreased in-person shopping and increased online shopping. We conducted a survey of 780 grocery shoppers in five Northeastern states in May 2020. The percent of groceries purchased online increased from 8.4% pre-COVID-19 to 21.1% during COVID-19, whereas the percent of purchases from physical stores declined from 85.3% to 72.4%. Increases in online purchases resulted from 1) an increase in the number of online users, and 2) an increase in the amount purchased online by pre-COVID-19 online users.