"Unless you have ever lived our life, you could never understand how we feel about it, and how much it is a part of us," said Assistant Tribal Chief Carl Custalow.
But downstream the city of Newport News, desperate for drinking water for its growing population, is laying claim to the river as well.
"We predicted that our supplies would probably be depleted should a serious drought occur, in the year 2000," said Dave Morris, a water official in Newport News.
Just upstream, the government plans to build a giant reservoir, one that would siphon off millions of gallons of water each day, and one that in the tribe's eyes would destroy its way of life.
"If it were your people that were being affected, how would you feel?" Custalow asked.
Tribal leaders are fighting the reservoir in court, claiming protection from a treaty they struck with Virginia in the 1600's. They say the reservoir will raise salt levels in the river and kill off the fish. City water officials disagree.
"We are not going to harm the river at all, so it's there to share," said Morris. "It's a resource of the Commonwealth and the United States, and all we're asking is to share the resource."
The City is asking the tribe to trust them. But after years of watching their lands disappear piece by piece in the name of development, the Mattaponi Indians are drawing the line at the river. It flows through their veins, they say, and they won't give up one drop without a fight.