West Ham United Football Club is an English professional football club based in Stratford, East London that competes in the Premier League, the top tier of English football. The club plays at the London Stadium, having moved from their former home, the Boleyn Ground, in 2016. The club was founded in 1895 as Thames Ironworks and reformed in 1900 as West Ham United. They moved to the Boleyn Ground in 1904, which remained their home ground for more than a century. The team initially competed in the Southern League and Western League before joining the Football League in 1919. They were promoted to the top flight in 1923 when they were also losing finalists in the first FA Cup Final held at Wembley. In 1940, the club won the inaugural Football League War Cup.
Three West Ham players were members of the 1966 World Cup final-winning England team: captain Bobby Moore and goal scorers Geoff Hurst and Martin Peters. The club has a long-standing rivalry with Millwall, and the fixture between the two teams has gained notoriety for frequent incidents of football hooliganism. West Ham adopted their claret and sky blue color scheme in the early 1900s, with the most common iteration of a claret shirt and sky blue sleeves first emerging in 1904.