According to Official Guinness Records,
The longest distance pushing a lawn mower in 24 hours by an individual is 92.71 km (57.6 miles) and was achieved by Jody Fassinger (UK) in Bournemouth, UK, from 16 to 17 December 2017.This attempt took place at King's Park Athletics Centre.
For a complete list of 2017 records, please visit 2017 Guinness Records in United Kingdom.