Phase equilibria in the La-1 xCaxFeO3 delta (LCF) system were assessed at temperatures below 1350 degrees C in both simulated air and argon atmospheres using a combination of differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and high-temperature X-ray diffraction. The solubility limit of Ca in the perovskite structure was determined to be 38% A-site substitution. A high-temperature orthorhombic to rhombohedral transition was identified and the dependence on oxygen partial pressure and effect on thermal expansion were characterized. A partial, pseudobinary LaFeO3-CaFeO2.5 phase diagram is presented that is based on these analyses combined with data available in the open literature.