Montgomery County (MD-VA)

Survey type M-Dz (magnetic; digitized from contour maps)
Flown by USGS
Date flown 04/58
Line spacing 0.4 (km)
Altitude 152.4 (m) above ground
Total distance 2,282 (km)
References
Counties Frederick - Montgomery - Fairfax - Loudoun
Overlapping surveys

Data: Magnetic, radiometric (M/R-Dz)