Rock Valley entered the tournament with a 9-0 record and were shooting for an unprecedented fourth straight state title but the third-ranked Blackhawks proved to be too much to handle.
Hinton never trailed in the game, leading 12-7 after one quarter of play and were 19-17 leaders at the half.
Rock Valley would pull no closer than four points in the second half only to see Hinton go on an 8-2 run and not look back.
Bridget Yoerget led Hinton with 13 points with six rebounds while Jamie VandeKooi added 10. Amber DeWeerd was the only Rocket in double figures with 11 points while Shayla Lange added nine points with four blocks.
Hinton (25-1) will face Fort Madison Aquinas or English Valleys in the Class 1A semifinals at 8 p.m. Wednesday.
Hinton (25-1) 12 7 15 9 -- 43
Rock Valley (20-7) 7 10 7 11-- 35