If you have 24 hours to spend in Hereford, there are a few things you should definitely consider doing:
1. Visit Hereford Cathedral: This beautiful cathedral dates back to the 11th century and is home to many treasures including the Mappa Mundi, a medieval map of the world. You could easily spend a few hours admiring the architecture and exploring the cathedral's history.
2. Walk along the River Wye: Hereford is located on the banks of the River Wye, making it the perfect place for a leisurely stroll. Enjoy the views of the river and the surrounding countryside as you walk along one of the many walking or cycling paths. Plan for around an hour or two, depending on how far you want to walk.
3. Visit the Hereford Museum and Art Gallery: This museum is home to a fascinating collection of artifacts that trace the history of Hereford and the surrounding area. From prehistoric times to the present day, there's something for everyone here. Give yourself at least an hour or two to explore and learn.
4. Shop in the Old Market: Hereford's Old Market is a great place to pick up souvenirs and locally-made products. There are also plenty of cafes and restaurants if you need a break from shopping. Plan for a couple of hours to explore and shop.
Overall, with one day in Hereford, you'll have plenty of options for things to see and do. Balancing between the four above will provide a great taste for the town & its history and with enough time, even more.