[3] As the river was not navigable beyond Elkridge, it was not a significant path of commerce; in 1723, only one ship was listed as serving the northern branch, and four others operating around the mouth.

[7] Milling and manufacturing operations abounded along the river throughout the eighteenth and nineteenth centuries, generally powered by small dams.

This is where Francis Scott Key, aboard the British HMS Tonnant, wrote "The Star-Spangled Banner", a poem later set to music as the national anthem of the United States.

[10] Efforts to remove Bloede's Dam began in the 1980s when nine drowning deaths occurred, and also to restore fish passage to a large portion of the Patapsco River watershed.

Liberty Dam and its reservoir on the North Branch are major components of the Baltimore City water system.

[17] The Patapsco River mainstem begins at the confluence of the North and South Branches, near Marriottsville, about 15 miles (24 km) west of downtown Baltimore.

The Bloede's Dam removal project was led by American Rivers and the Maryland Department of Natural Resources.

[1] The eastern portion of the Patapsco River is in a highly urbanized area and is subject to extensive stormwater runoff and other forms of water pollution.

The Maryland Department of the Environment has identified the Lower North Branch as containing high levels of heavy metals (chromium, arsenic, cadmium, copper, mercury, nickel, lead, selenium, and zinc), as well as phosphorus, fecal coliform bacteria, and PCBs.

[18] The Piney Run Reservoir on the South Branch of the Patapsco is polluted by excess levels of phosphorus and sediment.

[19] Environmental nonprofit organizations, such as The Friends of Patapsco Valley & Heritage Greenway, Inc. (PHG), lead clean-up efforts by the residents of surrounding communities.

The MD DNR stocks parts of Patapsco State Park in the early spring and offers some pretty decent trout fishing.