The solar cosmic ray Ground‐Level Enhancement (GLE) observed on 11 June 1991 was mildly anisotropic with a velocity dispersive onset. The anisotropy determined by comparing the flux observed by ‘‘forward viewing’’ high latitude neutron monitors with the flux observed by ‘‘reverse viewing’’ high latitude neutron monitors had an approximate 2‐to‐1 ratio at the GLE maximum. The relativistic proton flux anisotropy persisted through most of the GLE suggesting an extended high energy injection of particles. Using improved modeling techniques we have fitted a shock acceleration spectrum to both the neutron monitor observations and high energy (350 to 550 MeV) spacecraft data. The shock acceleration spectrum used to fit the observations has a differential rigidity slope of −4.62 at 1 GV at the GLE maximum implying a shock compression ratio of 2.237. ©1996 American Institute of Physics.