North-central N.H. '66 (NH)

Survey type M-Dz (magnetic; digitized from contour maps)
Flown by USGS
Date flown 12/66
Line spacing 0.8 (km)
Altitude 1676.4 (m) by barometer measurement
Total distance 2,897 (km)
References
Counties Oxford - Carroll - Coos - Grafton - Essex
Overlapping surveys

Data: Magnetic (M-Dz)