- Main article: List of Surviving Lonsdale Records
The list of Lonsdale Records relating to the Lowther family and the Earls of Lonsdale are stored at the Cumbria Record Office (Carlisle Headquarters). The Lowther Family Estate have thousands of records listed in various categories and sub-categories ranging from DLons/L5 to DLons/L25. The records relating to the 11th Border Regiment (Lonsdale) range from DLons/L13/13/1 to DLons/L13/13/282
D LONS/L13/13/279–282
12th (Reserve) Battalion / Earl of Lonsdale's Files
- D LONS/L13/13/279: Earl of Lonsdale's personal file re the Lonsdale Battalion - date: 31 August 1914 - 27 July 1916
- D LONS/L13/13/280: Papers re the arrangements for laying up the Battalion's colour at Lowther Church 9 September 1922 - date: August - September 1922
- D LONS/L13/13/281: Replies to invitations to the ceremony to lay up the Battalion's colour - date: August - September 1922
- D LONS/L13/13/282: Notices re a proposed tour by D Company to the battlefields - date: 1930
—For access to the above records please contact the Cumbria Archive Centre (Carlisle)