Studies have been made of the macroscopic and microscopic electrical inhomogeneity in undoped bulk GaAs single crystals grown from As/As+Ga melt ratios of 0.48–0.45. Microscopic inhomogeneity was characterized by contact resistance line scans and whole wafer anodization, which gives high‐resolution two‐dimensional images of the low‐resistivityp‐type regions within the wafers. The resistivity was nonuniform in wafers from 0.48 As/As+Ga crystals, having a W‐shaped radial dependence with minima in the ⟨110⟩ directions and varying by six orders of magnitude across a wafer, whereas it was uniform in low‐resistivity wafers from 0.45 As/As+Ga crystals at fractions of melt solidified,g>0.4. Precise correlation of microscopic inhomogeneity with grown‐in linear and cellular arrays of dislocations was obtained in nonuniform wafers, but no correlation with slip dislocations was observed. Anodization images show that the carrier concentration is quantitatively in agreement with a uniform acceptor background compensated by EL2 concentration fluctuations of factors of 2–3 at the dislocation networks. Inhomogeneity variation withgand As/As+Ga ratio is consistent with macroscopic and microscopic decrease in EL2 with melt stoichiometry.