Gillingham is a town in Kent, England, which forms a conurbation with neighbouring Chatham, Rochester, Strood and Rainham. It is the larg…Gillingham is a town in Kent, England, which forms a conurbation with neighbouring Chatham, Rochester, Strood and Rainham. It is the largest town in the borough of Medway and in 2020 had a population of 108,785.