Bythorn and Keyston is a civil parish in the Huntingdonshire district of Cambridgeshire, England. According to the 2001 census the parish had a population of 271, increasing to 316 at the 2011 Census. The parish was formed in 1935 by the merger of the parishes of Bythorn and Keyston. Now the A14 runs through the parish separating them as two different villages.