your gates: A typical town in ancient Israel was small, 4 hectares (about 10 acres) or less, and crowded. Most towns had few open areas.
One open space was an area just inside or outside the main gate. People used this area for public gatherings, including trials and other judicial events.
In this passage, the place is clearly outside the town. Stoning to death did not happen inside the walls (22:24; 1 Kings 21:10; see Deuteronomy 22:21).