Using the Westcott convention, the Westcott flux, φ w ; modified spectral index, r T n / T 0 ; neutron temperature, T n ; and gold-based cadmium ratios were determined for various sampling positions in the U.S. Geological Survey (USGS) Training, Research, Isotopes, General Atomic (TRIGA) Mark I reactor. Westcott parameters were determined by a bare multi-monitor method. Thermal-neutron temperature measurements were made using lutetium foils. The differential neutron energy spectrum measurement was obtained using the computer iterative code SAND-II-SNL. Measurement of the neutron spectrum has resulted in a better knowledge of the reactor core and will improve predictive radioisotope production calculations necessary for neutron activation analysis and medical isotope production.