The Chickahominy is an river in eastern Virginia. The river, which serves as the eastern border of Charles City County, rises about northwest of Richmond and flows southeast and south to the James River. The river was named after the Chickahominy Indian tribe who lived near the river when the English colonists arrived in 1607. Chickahominy descendants live in Charles City County today. During the American Civil War (1861–65), the upper reaches of the river became a major obstacle to Union General George B. McClellan's Peninsula Campaign, a failed attempt in 1862 to capture the Confederate capital of Richmond. Docile, narrow, and relatively easily crossed during dry weather, after periods of rain, the river expands across a flood plain with swamps as much as a mile across. The Chickahominy was in flood stage and divided the Union Army during crucial periods, despite continuous efforts by the United States Army Corps of Engineers to build and maintain bridges. Other battles were fought nearby in 1864. Part of a popular recreational area for boating, waterskiing, and sport fishing, featuring Walkers Dam and Chickahominy Lake, the lower Chickahominy River has become a major source of drinking water for the lower portion of the Virginia Peninsula in modern times. It also serves as a border for the Chickahominy Wildlife Management Area. The Chickahominy River is a Coastal Plain tributary to the James River with headwaters northwest of Richmond. For its first , the Chickahominy flows over igneous and metamorphic bedrock of the Piedmont, but soon becomes a Coastal Plain stream near Mechanicsville. The low-gradient Chickahominy sluggishly flows through broad swampy lowlands for from Henrico County to eastern New Kent County. southeast of Providence Forge, the Chickahominy River becomes an estuary and makes a turn towards to the south. When the sea level was higher during warmer (non-glacial) periods in the Pleistocene, the Chickahominy was a much broader river. The ancient riverbanks and meander loops are still recognizable.