A 3-NM-64 neutron monitor and a 2-MT-64 muon monitor were operated overland at 44 sites near sea level and on mountains in Canada, the USA, and Mexico in April, May, and June, 1965, when the intensity of cosmic radiation attained its 11-year maximum. The equipment is briefly described and the original results of the measurements are listed. Some necessary corrections for instrumental effects are discussed. The corrections made to eliminate the secular variations of the cosmic radiation and the dependence upon temperature structure of the atmosphere are given in detail. This paper is the first of a set of five dealing with latitude surveys made in 1965 and 1966. Reduction of the observations to a common pressure level is carried out in the final paper of the set.