Nakatsu Domain (中津藩 Nakatsu-han?) was a Japanese domain of the Edo period. It was associated with Buzen Province in modern-day Ōita Prefecture on the island of Kyushu. The domain was centered at Nakatsu Castle in what is now Nakatsu, Ōita.
In the han system, Nakatsu was a political and economic abstraction based on periodic cadastral surveys and projected agricultural yields. In other words, the domain was defined in terms of kokudaka, not land area. This was different from the feudalism of the West.
The hereditary daimyo were head of the clan and head of the domain.
Hosokawa clan, 1600-1632 (tozama; 399,000 koku)
Ogasawara clan, 1632-1716 (Fudai; 80,000->40,000 koku)