Labatt Memorial Park (formerly Tecumseh Park, 1877–1936) is a baseball stadium near the forks of the Thames River in central London, Ontario, Canada. It is 8.7 acres (35,000 m2) in size, has 5,200 seats and a natural grass field. From home plate to centre field the distance is 402 feet (123 m); from home plate to left and right field down the lines, it is 330 feet (100 m).
Labatt Park is the "oldest continually operating baseball grounds in the world", with a history dating back to 1877. Since December 31, 1936, Labatt Park has been owned by the City of London.
However, Fuller Field in Clinton, Massachusetts made it into the Guinness Book of World Records in September 2007 as the "world's oldest continually used baseball diamond/ field", dating back to 1878—a year after Tecumseh Park-Labatt Park opened in 1877—as Fuller Field's home plate and bases have purportedly remained in the same location since 1878, whereas home plate at Labatt Park has been moved (within the same field) from its original location in 1877.
In September 2008, however, Labatt Park replaced Clinton, Massachusetts' Fuller Field in the 2009 Book of World Records (page 191) as the "World's Oldest Baseball Diamond." Although it has flip flopped in the past, as of January 4, 2016, Guinness's online record for the World's Oldest Baseball Field/Diamond now states Labatt Park, London, Ontario. World's Oldest Baseball Field.
According to en.wikipedia