Magnetic and electric field fluctuations in the Pc 1 frequency range (0.2--5 Hz) have been observed by the polar-orbiting Viking satellite. The fluctuations, interpreted here as electromagnetic ion cyclotron (EMIC) waves, were observed during 21 of 450 orbits surveyed between 0900 and 1400 MLT, near 3 RE geocentric altitude, and at invariant latitudes from 59¿ to 77¿. The frequency structure of the waves is investigated, using spectral analysis and by determining the distribution of the wave frequency as a function of invariant latitude. At invariant latitudes from 59¿ to 72¿, EMIC waves were observed in the frequency range below the equatorial He+ gyrofrequency. This latitude structure of the wave frequency is discussed in terms of the linear growth rate dependence of the waves on the heavy ion density, ion anisotropy, and ion energy. The propagation characteristics of these waves were also investigated, using minimum variance analysis and polarization analysis, and by estimating the Poynting flux based on the observed magnetic and electric field. The waves had Poynting vectors directed downward toward Earth and reached magnetudes between 0.01 and 0.1 erg/cm2 s. The polarization of the waves was found to vary between linear, left-hand, and right-hand as a function of time or latitude. This variation is interpreted as the structure of spatially localized Pc 1 waves at high latitudes above the ionosphere. ¿ American Geophysical Union 1990