The Newburgh City Council on Tuesday passed a unanimous resolution against the planned Danskammer power plant project.
Orange County leaders voted to support the plan a little more than a week ago.
Newburgh joins the cities of Beacon and Peekskill in opposing the proposed new plant along the Hudson River.
Supporters say it will help the area's economy.
Opponents are concerned about environmental and health effects, as the plant will use fracked gas.