Historically, most launches from U.S. soil that have headed into a polar or near-polar orbit have been launched from Vandenberg Air Force Base in California. However, in a recent article written by James Dean of Florida Today, titled "Southbound? Cape rockets may fly new path toward poles", in which the possibility of flying into a polar orbit from Florida is now considered feasible, that in the early days of the space race, launches were indeed conducted on polar trajectories from Florida:
Cape launches most often head east to send satellites on their way around the equator. Polar trajectories have been avoided since a 1960 Navy launch inadvertently dropped a Thor rocket stage on Cuba, reportedly killing a cow.
Do we have a list of these satellites, their launching vehicle, and the date of their launch? Ideally, please only cite first hand sources, not forums.