According to USLegal, a class U misdemeanor is an unclassified misdemeanor. An unclassified misdemeanor is one that does not specify to any Class A, B or C misdemeanor. Unclassified misdemeanors vary by state, and the penalty is never very high.
USLegal states that an unclassified misdemeanor is usually a moderate offense. An unclassified misdemeanor likely entails a traffic ticket, such as driving with an expired license, an unpaid parking ticket or driving while impaired by alcohol. Unclassified misdemeanors normally come with a small fine and/or a short jail sentence. For example, in Oregon, the fine is normally under $1,000 for a single person, and imprisonment is limited to one year.