Magnetic susceptibility and remanence studies on late Eocene ash flow deposits of the Northeast Nevada Volcanic Field (NENVF) were undertaken at 39 sites in four sampling localities: Dolly Varden Mountains (20 sites), Nanny Creek area of the Pequop Mountains (11 sites), eastern Windermere Hills (7 sites), and southern Snake Mountains (1 site). These deposits span a narrow age range from 41.08 to 39.08 Ma based on 40Ar/39Ar data <Brooks et al., 1995a, 1995b> and on new K-Ar ages presented here. Characteristic remanences reveal that all ignimbrites sampled are reversely magnetized. The characteristic directions of remanent magnetization do not significantly deviate from the expected direction computed from the 42 Ma mean pole for North America, indicating that no major vertical axis rotations have affected the sampling regions since Eocene time. Anisotropy of magnetic susceptibility studies, undertaken to decipher flow trends and possible source areas for these ash flow tuff units of the NENVF, are consistent with a source region near the Toano Range. This places the ash flow source area east of Nanny Creek, the type area for the NENVF. The suspected source region lies close to the Wells fault system. However, Tertiary detachment faulting, Basin and Range normal faulting, erosion, and sedimentation have obscured the suspected source region. A more clearly defined zone of Eocene igneous activity, in the central Pilot Range to the east, cannot be ruled out as a potential source area.