​ CHICKAHOMINY, a river in Virginia, affluent of the James and running parallel to it for many miles from its source N. W. of Richmond. As it lay between the Union armies and Richmond, on and near it occurred many of the most important events of McClellan's Peninsula campaign in 1862, including the battles of Williamsburg, Hanover Court-house, Fair Oaks, Mechanicsville, Cold Harbor, Savage's Station, Frazier's Farm, and Malvern Hill. The second battle of Cold Harbor under Grant took place in 1864.