Yoita Castle was the seat of Naoe Kanetsugu, one of Kenshin's most trusted commanders. Kanetsugu served as Kenshin's close aide in governing Echigo and continued to serve the Uesugi after Kenshin's death. This castle is one of the fortifications that housed the loyal retainers across Echigo who gave the Uesugi military machine its remarkable organizational strength.

Yoita Castle, a mountain fortress in present-day Yoita-machi, Nagaoka, became Kanetsugu's base when he inherited the Naoe family name and lordship in 1581. From this castle he conducted his duties as chief administrator of the Uesugi domain, directing diplomacy and internal affairs. Until Kagekatsu was transferred to Aizu in 1598, Yoita Castle served as the headquarters of the Naoe house and a key node in the governance of the Uesugi territories.