AbstractMeasurements were made with a Lacoste–Romberg gravimeter G 88, along the Jos–Zaria–Sokoto and Zaria-Kano roads in order to establish a calibration line along which the constants of other gravimeters in Nigeria could be checked. Starting from the IGSN 7228J base station in Kano, the absolute gravity values for ten stations were determined. The maximum difference measured was 3340.89±0.16 g.u. (334.089±0.016 mgal) between Jos and Lambu Maradun about 80 km from Sokoto.