Hereford racecourse is to be closed down at the end of the year, while Folkestone racecourse is expected to be shut down on a temporary basis.
The Northern and Arena Racing Group have confirmed that Hereford will be closed down permanently, while Folkestone's future will depend on plans to build 800 houses on the ground.
Managing director of the enlarged Group, Tom Kelly said: "Hereford is owned by Herefordshire County Council and run under a lease arrangement. Attempts to extend the lease, which has 17 years remaining, have been unsuccessful.
"Despite being unviable for several years we have supported the racecourse but much-needed investment, required to breathe new life into the racecourse, cannot be justified in the absence of a long-term future for the business.
"Folkestone suffers from out-dated facilities and has been the subject of detailed discussion between the previous management, Arena Leisure, and Shepway District Council for several years now. The proposal for the site incorporated significant residential development, which would have enabled a new racecourse to be constructed with much enhanced amenities."
Kelly also confirmed that fixtures will be moved to other racecourses and prize money will be increased.