It got stuck around 6:30 p.m. on Wednesday, just north of the Ben Franklin Bridge in Philadelphia's Fishtown section, roughly between Penn Treaty Park and Petty Island.
Cargo ship runs aground along Delaware River in Philadelphia
The vessel, named "Algoma Verity," is a Supramax, self-unloading bulk carrier and measures 623 feet long.
Maritime tracking websites report the ship left port in Philadelphia at 5:30 p.m. on Wednesday and was headed for Fairless Hills, Bucks County.
The ship is carrying 45,000 tons of solar salt, according to the Coast Guard.
"We're looking for any signs of pollution in and around the vessel which could include the cargo, which happened to be solar salt, or diesel fuel," said Lt. Cmd. Patrick Frain of the U.S. Coast Guard.
So far there haven't been any leaks detected of either salt or fuel.
The Army Corps of Engineers will use specialized technology to determine what is causing the stoppage.
"To scan the bottom and identify any hazards and remove them immediately, and to prevent any further accidents," said Frain.
All ships are stopped from traveling the channel between Ben Franklin Bridge and Tioga marine terminal, about 3-and-a-half miles, until the ship can be moved.
To do so, crews will have to unload and redistribute the weight on board.
The Coast Guard is warning of abnormally low water levels through low tide Thursday night, and are advising ships to be aware. It's not clear yet it weather played a factor in this grounding.