Welwyn Hatfield Museum Service is a local authority museum service with trained, professional museum staff supported by casual staff and volunteers. The service cares for the historic and regionally significant Mill Green Mill (a Grade II * listed building) and Welwyn Roman Baths as well as social history, photographic and archaeological collections for the Welwyn Hatfield district.

"Our mission is to care for, provide access to and interpretation of our sites and collections for the benefit of the public. We hope to act as the focal point for community history and identity by providing a service which is people centred, accessible and available to everyone. We reflect the spirit of our sites and bring them to life through sharing cultural and historical knowledge and skills. We seek to provide lifelong learning opportunities in everything we do. We aspire to take a participatory approach in community engagement, to be led by the wants and needs of our community working together as equal partners."