Section 3(1)(b) in The Bihar And Uttar Pradesh (Alteration Of Boundaries) Act, 1968
(b)there shall be added to the State of Uttar Pradesh--(i)all the territories of Saran district of the State of Bihar lying between the fixed boundary and the deep stream of the river Ghaghra, and(ii)all the territories of Shahabad district of the State of Bihar lying between the fixed boundary and the deep stream of the river Ganga, and the said territories shall thereupon cease to form part of the State of Bihar.