Hōjō is a family name for several of the characters in the Higurashi universe. Specifically, the Hōjōs refers to the unnamed members of this family who are referred to in regards to their relationships with existing named characters. The Hōjōs who play an important role are the unnamed father and mother of Satoko and her missing older brother Satoshi. Teppei (and his wife Tamae) also shares this surname, as he is the brother of Satoko and Satoshi's stepfather.
The Hōjōs were supporters of the Dam Project in Hinamizawa and were shunned by all villagers. They were called "traitors" because most of the town was decidedly against the dam project, as it would flood Hinamizawa. Due to their parents' standing, Satoko and Satoshi were distrusted by most of the village as well. Eventually, the Hōjōs were killed when a deranged Satoko pushed them off a cliff while on a family vacation outside of Hinamizawa, on the night of the Watanagashi Festival.
In Meakashi-hen it was revealed that the Hōjō family is quite rich. Because of the cooperation during the Dam War, the goverment has payed big fortunes to the family. This fortune is the main reason of Satoshi's an Satoko's adoption by their uncle and aunt after their parents death.