Barnack is a village and civil parish in the Peterborough unitary authority of the ceremonial county of Cambridgeshire, England and the historic county of Northamptonshire. Barnack is in the north-west of the unitary authority, 4 miles (6.4 km) south-east of Stamford, Lincolnshire. The parish includes the hamlet of Pilsgate about 1 mile (1.6 km) northwest of Barnack. Both Barnack and Pilsgate are on the B1443 road. The 2021 Census recorded a parish population of 1000.