Is Ditmas Park part of Flatbush?

Yes and no. Ditmas Park is a distinct neighborhood and historic district, but it lies within the larger area historically known as Flatbush, and it is part of what is often called Victorian Flatbush, a cluster of neighborhoods known for their Victorian houses. So while people commonly refer to Ditmas Park by its own name, it is geographically and historically connected to Flatbush. The Ditmas Park Historic District gives it a defined identity of its own within that broader area.