By use of Kerr microscopy, the domain patterns of thin Fe films (10 nm) grown on Inx Ga1-x As (0.09 ≤ x ≤ 0.25)/GaAs substrates have been investigated. For This nvestigation, two types of InGaAs buffer layers were prepared. One consisted of a single, thick InGaAs layer and the second composed of an InGaAs strained layer superlattice. Both were grown on (100) GaAs substrates. The study showed that many of the domain walls were approximately parallel to the easy axis of Fe for those films grown on the low x alloy, e.g. x-0.1, InGaAs buffer layers. In the alloy films with larger values of x, e.g. x-0.2, the domain pattern of the Fe overlayer was strongly influenced by dislocations of the strain relieved InGaAs buffer layer. These dislocations manifested themselves as corrugations parallel to the <110> directions in the InGaAs. Kerr microscopy of a x-0.2 film indicated the presence of long, narrow domains with their long axes parallel to the striations. Although shape anisotropy arguments predicted that the magnetization should be parallel to the striations, magnetometer data indicated that a substantial component of magnetization was oriented perpendicular to the corrugations at low fields. The Fe film grown on the superlattice had magnetic domains very similar to a thick Fe film (0.5 μm) grown on GaAs.