We collected data on why UK museums had closed and on what had happened to their collections and other objects. Wherever possible we found out who had acquired the collection, under what circumstances, when, and the objects’ new locations, if relevant. We obtained our information from the following sources: 
•	Local and national newspapers
•	Subject-specialist journals, newsletters, and mailing lists
•	Charity Commission, Companies House, Scottish Regulator files
•	Liquidators’ reports
•	Closed museums’ websites (extant and via the Internet Archive Wayback Machine)
•	Defunct and current social media 
•	Online reviews, blogs, and chat forums

We followed leads by email and telephone, contacting former volunteers, members of staff, and family members as appropriate. We also put out calls for help via social media and contacted staff in:
•	Subject-specialist networks
•	Enthusiasts, preservation, and historical societies
•	Local councils and their museum services
•	Neighbouring museums
•	Neighbouring businesses
•	Tourist offices

The material was cross-checked by the research team. Staff from each of the Museums Development Networks, Museums Galleries Scotland, and the Northern Ireland Museum Council reviewed and helped refine our lists of closed museums.  

We integrated the data on closure with our Mapping Museums dataset. This has information on all the museums open in the UK between 1960 and 2020, their address, governance, size, and subject matter, accreditation status, years of opening and, if relevant, closure. We have continued to check for new and closed museums and to update the Mapping Museums and Museum Closure databases accordingly. Updates come from four main sources:
•	Museums Journal news and announcements
•	Google alerts and online searches
•	Regular communication with the Museums Development Network
•	Direct contact with museum staff

The finalised Museum Closure dataset comprises a list of museums in existence in the UK during 1960-2025 and their characteristics, with detailed information on museum closure from 2000 and after.