Kate Winslet insisted that they keep to the Delco accent which is common to that area of Pennsylvania. It's a difficult accent to master but Winslet felt that the community was such an important element to the show that they would be doing the area a disservice if they didn't at least try. She found learning the accent to be extremely taxing to the point that she often ended up throwing things.
The sex scene was re-shot in order to tone down the nudity and sexuality of the scene - the first version was on the bed, but was replaced with a second version on the couch.
Production was halted for six months due to the Covid-19 pandemic. This gave Kate Winslet flashbacks to when she made Contagion (2011), which ironically became a Netflix binge hit during lockdown.
Easttown is a township in Chester County, Pennysylvania. The show's writer, Brad Ingelsby, grew up in the locality.