AbstractIt is common knowledge that if we level without error from a point A to another point B along two different routes, the two height differences thus obtained in going from A to B will generally not be equal. This lack of equality may be due to the effect of gravity on the levelling and any levelling not corrected for this effect will not always result in the actual height difference between the points. Furthermore, the effect is expected to show up as a systematic error in the circuit closures when the level network is computed.This paper examines the effect of the gravity correction in the circuit closures which arose in the Nigerian Levelling.