Using free field acoustic stimulation conditions, the spatial response areas of single neurons and auditory space representation in the inferior colliculus (IC) of the big brown batEptesicus fuscus, was studied under different ear positions. A best frequency stimulus was delivered from the loudspeaker which was moved manually across the frontal auditory space of the bat to determine the response center of the neuron. At the response center, the neuron had its maximal directional sensitivity. The spatial response area of each neuron was determined for acoustic stimuli set at several intensity levels above the minimum threshold of the neuron. The spatial response areas of each IC neuron expanded unsymmetrically with the stimulus intensity. The size of the spatial response area was not correlated with the minimum threshold, best frequency, or recording depth of each neuron. Although each neuron had a point of maximal directional sensitivity, the point‐to‐point representation of the auditory space was not systematically organized. This representation was not correlated with the recording site of each neuron in the mediolateral, posteroanterior and dorsoventral axes of the IC. Both the response centers and spatial response areas of individual neurons varied with ear position but individual variations were complementary. It is likely that a mobile auditory space representation may provide the bat with versatility in maximizing the directional sensitivity of its echolocation system for accurate prey capture. [Work of Philip Jen supported by NIH.]