According to Official Guinness Records,
The greatest distance on a human-powered vehicle in 24 hours is 1,041.24 km (647 m) and was achieved by Greg Kolodziejzyk (Canada) at Redwood Acres Raceway in Eureka, Alberta, Canada, on 18 July 2006.
For a complete list of 2006 records, please visit 2006 Guinness Records in United States.