Trevithick Day is an annual event held in Camborne, Cornwall, England, to celebrate the life and achievements of Richard Trevithick, a Cornish engineer who is credited with inventing the first practical steam locomotive. The event is held on the last Saturday in April, which is the anniversary of Trevithick's first public demonstration of his steam locomotive, the Penydarren, in 1804.

Trevithick Day is a family-friendly event that features a variety of activities, including steam engine demonstrations, live music, street entertainment, and a parade. There are also stalls selling food and drink, and a number of educational exhibits about Trevithick and his work.

The event is organized by the Trevithick Society, a local group dedicated to preserving Trevithick's legacy. The society was founded in 1964 and has been running Trevithick Day since 1967.

Trevithick Day is a popular event that attracts thousands of visitors from all over the world. It is a celebration of Cornish engineering and heritage, and it is a fitting tribute to a man who is considered to be one of the most important figures in the history of transportation.