The borough is named after Runnymede, a water meadow on the banks of the River Thames near Egham, which is connected with the sealing of Magna Carta by King John in 1215.

The M25 motorway which encircles London runs through the borough, with Addlestone, Chertsey and Egham Hythe being inside the M25.

[3] The neighbouring districts are Spelthorne, Elmbridge, Woking, Surrey Heath and Windsor and Maidenhead.

[6] The district was awarded borough status in 1978, allowing the chair of the council to take the title of mayor.

Following the 2024 election a coalition of Labour, Liberal Democrats, Greens and independent councillors formed to run the council.

The council's former offices were on the adjoining site and were subsequently demolished to make way for a retail development.