Virginia's Three Major Regional Watershed Systems

Virginia's hydrology is defined by three primary watershed systems:

• Chesapeake Bay Watershed: Largest in Virginia (>64,000 sq mi), encompassing the entire bay and tributaries; diverse habitats including forests, wetlands, marine ecosystems.
• Roanoke River Watershed: Largest river basin in the state (>15,000 sq mi), covering the Roanoke River and tributaries; habitats span forests, mountains, piedmont.
• James River Watershed: Second largest river basin (>10,000 sq mi), includes the James River and tributaries; forests, wetlands, marine ecosystems.

These watersheds are critical for water supply, ecology, and regional planning across the Commonwealth.