[en] Properties of the hadronic final state in photoproduction events with large transverse energy are studied at the electron-proton collider HERA. Distributions of the transverse energy, jets and underlying event energy are compared to anti pp data and QCD calculations. The comparisons show that the γp events can be consistently described by QCD models including - in addition to the primary hard scattering process - interactions between the two beam remnants. The differential jet cross sections dσ/dE_T^jet and dσ/dη^jet are measured. (orig.)