By 1614, the English settlers had occupied much of the land along the James River and were beginning to establish farms on the York River. The territory controlled by Powhatan was reduced as the English expanded out from Jamestown. The Algonqian ruler was forced to move west from his original capital at Werowocomoco to Orapakes in 1609, and ultimately Powhatan settled at the headwaters of the Pamunkey River at Matchut.
According to Helen Rountree,Powhatan moved from Orapakes to Matchut between 1611 and 1614. Matchut was located on the northern bank of the Pamunkey (upstream of the modern Route 360 highway crossing), in a location where the English could not reach by sail before the Native Americans would be able to respond to a water-based attack. (The new capital 1
The new location offered better water access for Powhatan to receive corn provided by his subordinate werowances, and offered better farmland for local production compared to the swamps at Orapakes. Most importantly, Matchut was far enough away from the English for Powhatan to feel secure. Locating Matchut on the northern bank of the Pamunkey put another water barrier between the capital of the Algonquians and the English, providing some protection against a ground attack.
While more secure, we know that Matchut was accessible to the English. According to Ralph Hamor, Matchut was a two-day trip from Bermuda Hundred ("the Bermuda") on the south bank of the James River. In 1614 he visited Powhatan to negotiate a marriage between Sir Thomas Dale, the leader of the English Colony, and one of Powhatan's daughters. 2
Dale hoped such a marriage would bring an end to warfare between the Powhatan tribes and the English. After Powhatan rejected the proposal, Dale tried to pressure Powhatan by bringing Pocahontas to Matchut. Dale proposed to exchange Pocahontas in return for the settlers that had fled to the Algonquian towns, and for the English tools and weapons they had stolen. In the second trip to Powhatan's capital, Dale sailed with 150 men to the Pamunkey River. According to Hamor's account (obviously written from the English point of view, with phrases such as "justly provoked"):
Obviously Matchut was not completely inaccessible to land-based sorties from the English sailing ships. Later, after further negotiations, Powhatan agreed to let Pocahontas marry John Rolfe and to live in peace with the English (but Powhatan never agreed to a marriage between Dale and any Native American).

When Powhatan moved the confederacy's capital moved to Matchut, Opechancanough lived across the Pamunkey River at Youghtanund. When the Algonquian chief Powhatan died in April 1618, his younger brother Opitchapam assumed authority. However, it appears Opechancanough controlled the confederacy's dealing with the English, and Opitchapam lacked full control or served just as a "front man" for Opechancanough.
Apparently the peace associated with the marriage of Pocahontas-John Rolfe was made over objections by Powhatan's younger brother, Opechancanough. Opechancanough organized the Great Uprising of 1622, when the Algonquians dropped the appearance of peaceful coexistence and attacked the English settlements.
The English response to the Great Uprising in 1622, and to another one in 1644, was to kill or displace most of the Algonquians living in Tidewater and to destroy the Powhatan confederacy. Those two wars greatly disrupted the capacity of any single Algonquian leader to control multiple tribes in eastern Virginia.
The last "capital" of the organized Powhatan confederacy was apparently Matchut. Today there are seven state-recognized tribes in Virginia that have ties to the original confederacy (plus an eight tribe based in Amherst County). Two of the old Algonquian tribes have reservations on the Pamunkey and Mattaponi rivers, but each Algonquian tribe has their own center and no tribe is subordinate to another.