Surrey Police were called to Epsom Derby on Saturday 4 June to deal with increasing violence between race-goers.
More than 100,000 people attended the two-day event, with the Queen and Prince Philip also making an appearance on Saturday.
Police officers armed with riot shields arrived to break up multiple scuffles taking place near the racecourse throughout the day. The violence resulted in one man being hospitalised with head injuries and 11 arrests, including three for drug offences and four for affray.
Temporary chief superintendent Jerry Westerman of Surrey Police said: “The Investec Derby Festival is a hugely popular event attracting many thousands of people from both the local area and wider afield. The majority of visitors come to have a good time and enjoy themselves and it is a small minority who cause trouble and spoil the atmosphere.
“Surrey Police will not tolerate this kind of behaviour and anyone who can assist officers with their investigation is urged to do the right thing and come forward.”