Where are neurons located in the body?

All over. There are 3 different neuron structures: Multipolar(purkinje cells and pyramidal cells), bipolar and unipolar. The multipolar neurons are found in the brain and spinal cord. Bipolar neurons can be found in the retina (eye) and olfactory cells (nose), for example. Sensory receptors are the dendrites of Unipolar neurons that run to and through the spinal cord.