This is interesting. Marylandfag here. ZIP code 20850, Rockville, Montgomery County, MD is basically the DC area's new Chinatown. (The old DC Chinatown partially vacated when the Metro station went in). Huge variety of Chinese restaurants, grocery stores, and other businesses in the downtown Rockville area, surrounding the gov't buildings and post office and continuing N and S on Rockville Pike.

Fairly low COVID-19 cases for the Rockville zip (it does not appear on the list when scrolled). I think it went through here in January or early February 2020. I had a productive cough and post-nasal drip at that time, way too early for pollen. Was eating out at Chinese restaurants 3-4x a week, at least once a week in downtown Rockville. If anyone could have caught it then, I should have. But I won't know until there's an accurate antibody test widely available.

Pic-related was capped from https://coronavirus.maryland.gov/