When Ieyasu was transferred to the Kanto region in 1590, Tadakatsu was given 100,000 koku, the second biggest crop yield among the vassals (Naomasa II had the biggest as 110,000 koku), along with Yasumasa SAKAKIBARA from Otaki, Kazusa Province (Otaki Town, Isumi County, Chiba Prefecture).
天正18年（1590年）、家康が関東地方に移封されると上総国大多喜（千葉県夷隅郡大多喜町）に榊原康政と共に、家臣団中第2位の10万石（1位は井伊直政の11万石）を与えられる。