In my generation especially a lot of people in the US have been raised with a very Christian background. Some people were super strictly religious. Some families were not quite so religious - sort of non-practicing but claimed the background anyhow. That' a lot more common among Protestant folks in this area.
Most people that I work with or people that I've spoken with in the past have heard the term Wicca. It’s like anyone who has ever explored “alternative” forms of spirituality have come across Wicca.