Museums, Librarys have worked for me. Years ago when I was in the library in near by Charles town they had a big Jefferson County map 1850 something on the wall. They told me were I could get one. Loudon County found one (1850"s) at the museum. Winchester Visiter Center sent me to the museum next door and I got old maps of City of Winchester, the valley and 3 others. (Paid $15 or $20 bucks for all 5).