The Maidstone line is a railway line between Swanley, Maidstone and Ashford in Kent, England. The line diverges from the Chatham Main Line at Swanley Junction and proceeds down the Darenth valley to Otford junction (where the Bat & Ball line divides towards Sevenoaks). It continues via Borough Green & Wrotham and Maidstone East to Ashford, where it joins the South Eastern Main Line. In 2020 the line from Ashford International to Kemsing was adopted by the Kent Rail Partnership and this section was renamed The Kent Downs Line