- 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/L13/13/275–278
12th (Reserve) Battalion / Miscellaneous
- D LONS/L13/13/275: Local press cuttings mainly re the formation of the Battalion - date: 15 September 1914 - 8 May 1915
- D LONS/L13/13/276: File including: copy of telegram re founding of the battalion, list of applicants for appointment as officers, denominational rolls - date: 6 September 1914 - 15 August 1915
- D LONS/L13/13/277: Miscellaneous printed records - date: 1914 - 1915
- D LONS/L13/13/278: Miscellaneous papers - date: 9 September 1914 - 29 November 1915
—For access to the above records please contact the Cumbria Archive Centre (Carlisle)