1861

• Soil runoff from farms of Prince George's County, Maryland contributes to increased silting in the Potomac River.
• Civil War demands for timber for cooking and fuel deforest many stretches of the Potomac River Banks.

1870

• The Army Corps of Engineers dredges the Potomac to keep it navigable.

1881

• The U.S. Fish Commission hires seiners to catch shad and herring on the Potomac River.

1885

• "Oystermen" harvest 15 million bushels of oysters in Maryland waters.

1890

• Rock Creek Park is created to preserve some of the natural and historic resources within Washington, D.C.

1892

• Shad and herring fish hatcheries are built at Fort Washington and Bryan's Road in southern Maryland.