We report the confined compression strengths and Young’s moduli of coal and roof rock from the Upper Freeport seam, Lucerne No. 6 Mine, Homer City, Pennsylvania, the Lower Kittanning seam, Kitt No. 1 Mine, Phillipi, West Virginia, and the Soldier Canyon seam, Soldier Canyon Mine, Price, Utah. A total of 210 tests to failure in biaxial compression were performed at confining pressures of 0.1, 3.0, and 10.0 MPa. The strengths increase by a factor of 2–3 over the confining pressure range, while the Young’s moduli are about constant. Standard deviations are 10–30% of the mean, emphasizing the need to do many tests. Failure in all three coals is brittle, progressing from dilational to multiplane shear to single‐plane shear on increasing confining pressure. Strengths and moduli could not be correlated with such macroscopic inhomogeneities as large cracks, voids, and compositional changes.