Bay History

From the Chesapeake Bay Program (

The Chesapeake region has been around for a very long time. Many tend to begin its history with the establishment of Jamestown, Virginia, in 1607. But the story of the Bay began millions of years before that.

35 Million Years Before Present (BP)

  • A rare bolide — a meteor- or comet-like object from space — hits the area that is now the lower tip of the Delmarva Peninsula, near Cape Charles, Virginia, carving out a 55-mile wide basin. While this bolide did not actually create the Bay, it helped determine that a bay would eventually be located there.
  • Sea levels fluctuate over the next few million years. The area that is now the Chesapeake Bay alternates between dry land and the floor of shallow coastal seas.

10 to 2 Million Years BP

  • A series of ice ages lock ocean water in massive glaciers, causing the mid-Atlantic coastline to extend 180 miles farther east than its current location. Glaciers melt during warmer periods, inundating the Coastal Plain with sand, gravel, silt and clay. In colder periods, thick conifer forests dominate, attracting deer, bears, mammoths and numerous bird species.

2 to 3 Million Years BP

  • Melting glaciers carve channels through the Coastal Plain. These will one day become the rivers that flow to the Chesapeake Bay.

15,000 Years BP

  • A landscape dominated by conifers begins transitioning to a mix of hardwood species, such as oak, maple and hickory.
  • A warming climate promotes the spread of freshwater wetlands and coastal salt marshes.
  • Small populations of Paleoindians settle in the Bay region.

2000 BC

  • The Bay more or less assumes its current shape: roughly 190 miles long, 35 miles across at its widest point, and an average depth of 22 feet.
  • Native American populations now live throughout the region and develop more sophisticated hunting methods, such as the bow and arrow.
  • Mammoths are no longer present in the region. The Bay's waters are now dominated by oysters, clams and fish such as bass and shad.

1000 BC

  • Native American agriculture results in more permanent town villages.


  • The Native population reaches 24,000.
  • Spanish and French explorers reach the Chesapeake Bay. Italian Captain Giovanni da Verrazano writes of meeting natives on his 1524 voyage sponsored by France. In 1570, Spanish priests voyage up the James River.


  • An influx of Europeans settlers come to the Chesapeake Bay region to grow tobacco in large plantations.
  • The first small cities develop in Jamestown, Williamsburg, Annapolis and St. Mary's.


  • The first English settlement is established in Jamestown, Virginia.
  • Captain John Smith begins his exploration of the Chesapeake Bay.


  • The Colonists establish booming businesses in ship masts and timber. They clear land for agriculture and use hook and line to catch fish in the Bay's shallow waters.
  • The colonial population is estimated at 13,000, but only 10 percent of an estimated 24,000 native people remain.


  • The colonial population grows rapidly as agriculture expands, resulting in the first signs of environmental degradation.
  • European immigrants continue to steam into the region, creating a patchwork of rural farming and fishing communities on the Bay's western and eastern shores.


  • The colonial population reaches 380,000; one-third of the population is made up of slaves.
  • Colonists strip 20 to 30 percent of the Chesapeake region's forests for settlements.
  • Bay shipping ports begin to fill with eroded sediment and become too shallow for navigation.
  • Commercial fishing for species like shad and herring begins.


  • Farmers begin to use plows extensively, starting a cycle of permanent tillage that prevents reforestation and starts a massive period of soil erosion.
  • The colonial population exceeds 700,000.


  • After eight years of fighting, the Revolutionary War ends with the surrender of British Lord Charles Cornwallis at Yorktown, Virginia. The former British colonies are about to become the beginning of a new unified nation, with the Chesapeake Bay region serving as a key economic and political center.


  • Virginia and Maryland sign the Compact of 1785. Virginia agrees to give vessels bound for Maryland free passage at the entrance to the Chesapeake Bay in return for an agreement by Maryland that the right to fish in the Potomac River was to be enjoyed by citizens of both states.


  • The Bay region population reaches one million.
  • Oyster harvests increase, with 3,200 oyster boats in Maryland and 4,400 in Virginia.


  • Baltimore is a major American port and the nation's third largest city.
  • The advent of the steamboat replaces sailing ships increasing the speed of water transit for people and goods.


  • The 25-year Chesapeake & Delaware canal project is completed, linking Chesapeake Bay with Delaware Bay. The project opens up undeveloped lands to timbering and farming.


  • Half of the forests in the Chesapeake Bay region have been cleared for agriculture, timber and fuel for homes and industry.
  • The first imported fertilizers are used after ships bring bird guano from Caribbean rookery islands and, later, from nitrate deposits on the Chilean coast. In the years that follow, increased agricultural runoff will promote algae blooms.


  • Baltimore is a bustling urban and industrial center with a population of one million.


  • Nearly 60 to 80 percent of the forests in the Baltimore-Washington corridor have been cleared for agriculture and development.
  • Chesapeake Bay waters become more polluted as coal-burning industries spew smoke and dump wastes in Bay tributaries, and cities dump raw sewage into the Bay.
  • The Chesapeake Bay region's population exceeds 2.5 million.


  • Railroad tie replacement consumes an estimated 15 to 20 million acres of eastern forests.
  • Steamships and railroads allow fish, crabs and oysters to be sold and shipped to distant cities.
  • The region's population exceeds three million.
  • Noting declines in shellfish beds, scientists increase their efforts to study human impacts on aquatic life in the Bay.


  • A Washington, D.C., law states that new buildings may not be more than 20 feet taller than the width of the street in front of the building. Since the city can not build upward, it begins to expand outward.


  • Baltimore is the last major American city to install sewer lines, but one of the first to adopt a waste treatment system. The system is installed to help save valuable oyster beds.


  • The University of Maryland Chesapeake Biological Laboratory is founded.
  • The first water quality surveys indicate the Bay is in good shape, except in heavily industrialized areas.


  • The region's population exceeds 4.5 million.


  • Conowingo Dam is constructed near the mouth of the Susquehanna River.


  • The Bay region's population exceeds five million.
  • The Great Depression spurs public works projects to repair and extend the region's roadways, bridges, parks and electrical services to rural areas. This encourages more population growth in undeveloped locations.


  • An interstate conference on the Chesapeake Bay is held. The concept of treating the Bay as a single resource unit is developed.


  • Widespread use of chemical fertilizers begins.
  • The human population explodes and the “suburb” is born.
  • Improvements in fishing equipment technology cause many fish populations to decrease.
  • With the conclusion of World War II, shipyards in Chesapeake Bay cities such as Baltimore and Norfolk experience a five-year boom to supply the war effort.


  • Both Maryland and Virginia have water pollution control agencies in place.


  • All over the Bay region, developers drain and fill wetlands to build housing and suburban centers. Water and air pollution continue to plague the Bay.
  • Calvert County, Maryland, resident Bernie Fowler can see his white sneakers after wading out to his shoulders in the Patuxent River. The clear water is a sign of good, healthy water quality.
  • MSX and Demo — two diseases that kill oysters — appear in the Chesapeake Bay. These diseases wipe out most of the Bay's native oysters by 2000.


  • The 4.2 mile long Chesapeake Bay Bridge is constructed, connecting Anne Arundel County, Maryland, to Kent Island and opening up the Eastern Shore to development.


  • The 17.4 mile long Chesapeake Bay Bridge-Tunnel opens, connecting Virginia's Eastern Shore to Virginia Beach, Virginia.


  • In his State of the Union address, President Lyndon B. Johnson pledges that the Potomac River will become a “model of beauty and recreation” for the country.
  • Construction of interstates 66, 70, 83, 95, 270, 495 and 695 is completed, signaling that the personal car has become the choice mode of transportation for Americans.


  • The Chesapeake Bay Foundationis created.


  • The federal Clean Air Actis passed.
  • A trend of increasing forest cover reverses due to population growth and development. People and businesses begin to migrate to urban centers.
  • The Susquehanna River Basin Commission is established by the federal government and the states of New York, Pennsylvania and Maryland.
  • Chesapeake Bay jurisdictions enact laws to protect wetlands.
  • There is a dramatic decline in underwater bay grasses due to increasing sediment and nutrient pollution flowing from new development.


  • Tropical Storm Agnes ravages the region, destroying many underwater bay grass beds.
  • The federal Clean Water Actis passed, establishing water quality standards and limiting the amount and type of pollutants entering Chesapeake Bay waterways.
  • The pesticide DDT is banned.
  • The Alliance for the Chesapeake Bayis formed to ensure public participation in policy decisions affecting the Bay.
  • U.S. Senator Charles Mathias (R-MD) successfully introduces legislation that directs the EPA to conduct a five-year study and produce a report on the Chesapeake Bay.


  • The Chesapeake Bay Commission, a tri-state legislative body, is created.


  • Biological nutrient removal (BNR)is introduced at wastewater treatment plants on the Patuxent River after three Maryland counties sued the state and the EPA over the river's dirty, unhealthy water.


  • The congressionally mandated EPA report on the Chesapeake Bay is completed. It highlights four areas that require immediate attention: an overabundance of nitrogen and phosphorus pollution; dwindling underwater bay grasses; toxic chemical pollution; and over-harvesting of living resources.
  • The Chesapeake Bay Program, a unique voluntary partnership, is established with the signing of the first Chesapeake Bay Agreement by Maryland, Pennsylvania, Virginia, the District of Columbia, the Chesapeake Bay Commission and the EPA. The agreement establishes the Chesapeake Executive Council as the Bay Program's chief policy-making authority.


  • The Bay Program initiates the Chesapeake Bay Water Quality Monitoring Program.
  • The first federal agency agreements are signed between EPA and the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA).
  • The Maryland legislature passes the Chesapeake Bay Critical Areas Protection Act, a plan to control development along the shores of the Bay and its tidal rivers.


  • The Alliance for the Chesapeake Bay begins a first-of-its-kind volunteer citizen water quality monitoring program.
  • Maryland places a moratorium on fishing for striped bass.
  • A phosphate detergent ban is enacted in Maryland. Washington, D.C., follows in 1986, Virginia in 1988 and Pennsylvania in 1990.


  • The Bay Program initiates its first nutrient management efforts.
  • Mute swan populations increase in the Chesapeake Bay. The swan causes damage to underwater grass beds and competes with the native tundra swan.


  • The 1987 Chesapeake Bay Agreement is signed by Bay Program partners. The 1987 Agreement sets a goal to reduce nitrogen and phosphorus entering the Bay by 40 percent by the year 2000. It also directs the Bay Program to study atmospheric inputs to the Bay.


  • Virginia adopts the Chesapeake Bay Preservation Act to provide land use guidance to local governments.
  • Bernie Fowler, now a Maryland state senator, wades into the Patuxent River. Water clarity is so poor he cannot see the tips of his white sneakers beyond 10 inches deep.


  • The Chesapeake Bay Basin-wide Toxics Reduction Strategy is adopted.
  • The Chesapeake Bay Wetlands Policy, which commits the Bay Program partners to a goal of “no net loss” of wetlands, is adopted.
  • Virginia places a moratorium on fishing for striped bass.


  • The federal Clean Air Act amendments establish the Great Water Bodies Program, which acknowledges air deposition as a contributor to water pollution.
  • Striped bass moratoria are lifted and limited harvests are allowed in Maryland and Virginia.


  • The Chesapeake Bay Agreement 1992 amendmentsare issued, giving nutrient reductions a tributary focus. The amendments call for a permanent nutrient cap after 2000.
  • More than 450,000 acres of land in the Chesapeake Bay region are under nutrient management plans.
  • The Maryland Motor Vehicle Administration begins selling “Treasure the Chesapeake” license plates, which support the Chesapeake Bay Trust.


  • The Bay Program issues directives addressing tributary strategies: regional action plans to reduce toxics, restore underwater bay grasses, open fish passage and reduce agricultural pollution.
  • Pennsylvania enacts a law requiring large animal farm operations to implement nutrient management plans.


  • Twenty-five agencies and departments sign the Agreement of Federal Agencies on Ecosystem Management in the Chesapeake Bay.
  • Nearly one million acres of land in the Chesapeake Bay region are under nutrient management plans.
  • The 1994 Chesapeake Bay Basin-wide Toxics Reduction and Prevention Strategy is adopted.
  • New initiatives begin for riparian forest buffers, habitat restoration, aquatic reef restoration and reciprocal agricultural certification programs.


  • The striped bass (rockfish) stock is declared restored by the Atlantic States Marine Fisheries Commission.
  • The Local Government Partnership Initiative is signed, engaging the watershed's 1,650 local governments in the Bay restoration effort.
  • The Public Access Guide is released, highlighting more than 500 public access sites throughout the Chesapeake Bay watershed.
  • Adoption statements on ballast water and pesticide management are signed.
  • Maryland creates 10 watershed-based tributary teams to bring Chesapeake Bay cleanup to the local level.


  • Record high flows are recorded as a result of heavy winter snowfall and Hurricane Fran.
  • The Bay Program launches the Businesses for the Bay program.
  • Toxics Regional Action Plans are finalized for the Elizabeth River, Baltimore Harbor and the Anacostia River.
  • The Local Government Participation Action Plan is adopted, reaffirming the Bay Program's commitment to strengthening its partnership with local governments.
  • The Priorities for Action for Land, Growth and Stewardship in the Chesapeake Bay Region is adopted, addressing land use management, growth and development, stream corridor protection and infrastructure improvements.
  • The new Riparian Forest Buffer Initiative calls for conserving existing forests along streams and sets a goal to restore 2,010 miles of forest buffers along streams and shorelines by the year 2010. That goal is reached in 2002 and expanded in 2003.
  • The largest wastewater treatment facility in the Chesapeake Bay region, the Blue Plains Wastewater Treatment Plant in the District of Columbia, begins BNR for half of its flow capacity.
  • Virginia passes the Agricultural Stewardship Act, considered to be the most far-reaching "bad actor" law in the nation for controlling agricultural pollution.


  • The 1997 Nutrient Reduction Re-evaluation concludes that the 40 percent nutrient reduction goal is in sight.
  • Maryland, Pennsylvania and Virginia all have successful agriculture nutrient management certification and education programs in place. Approximately 1.7 million acres in the Bay region are under nutrient management.
  • Installation of the BNR pilot at Blue Plains leads to record reductions of nitrogen discharges into the Potomac River.
  • Pfiesteriapiscicida, a toxic dinoflagellate, is discovered in three tidal tributaries of the Bay, causing fish kills and raising concerns about the impact of nutrient pollution on human health.
  • Less nitrogen and phosphorus are found in the Bay's waters compared with previous years.
  • Maryland adopts a series of Smart Growth and Neighborhood Conservation initiatives aimed at directing growth and enhancing older developed areas.
  • Virginia passes the Water Quality Improvement Act, setting a process for establishing goals and providing funds for both point source and non-point source improvements.
  • Pennsylvania establishes the 21st Century Environment Commission to determine environmental priorities for the next century.


  • Maryland adopts a bill that requires farmers to implement management plans to reduce both nitrogen and phosphorus.
  • The federal Clean Water Action Plan provides a blueprint for restoring and protecting the nation's waters using the Bay Program as a model. It is later implemented in the Chesapeake Bay region with the signing of FACEUP (Federal Agencies' Chesapeake Ecosystem Unified Plan).
  • American Forests kicks off the Global ReLeaf for the Chesapeake campaign to plant one million trees in the Bay region by 2000.
  • Small Watersheds Grantsare awarded to 17 local communities and 20 citizen groups in the Bay watershed to assist with on-the-ground restoration projects.
  • Bay Program data confirm that industries showed a 67 percent reduction in toxic releases in the Bay region between 1988 and 1996.
  • The Blue Plains Wastewater Treatment Plant commits to full BNR by 2000.
  • The Atlantic States Marine Fisheries Commission closes the entire East Coast to Atlantic sturgeon fishing for the next 40 years, the longest fishing moratorium on record.
  • Virginia announces it will spend $48 million on new clean water programs.
  • Pennsylvania Governor Thomas Ridge issues an executive order to establish land use goals and assist local governments in implementing sound land use objectives.
  • The Chesapeake Executive Council signs directives that make education, a renewed Bay Agreement, technology and animal waste management top tools for the future. The Chesapeake Bay Program Education Directive determines convening an Education Summit of the four interagency education groups in 1999 and every two years thereafter.
  • The last of five dams on the James River is breached. A fish ladder added to Bosher's Dam opens the river from Richmond to Lynchburg, Virginia.