Demonstrators rallied in Center City against the Dakota Access pipeline in North Dakota.
The protest is part of a series of events across the country in an effort to halt the controversial pipeline.
About 200 people were protesting near City Hall on Tuesday morning. The demonstration was ending by about 10 a.m.
The large crowd led to traffic delays in the area.
Members of the Standing Rock Sioux tribe have been protesting the oil line, which will travel under the Missouri River. The tribe says the pipeline threatens drinking water and cultural sites.
The Philadelphia protest has been peaceful.