Mud Island Shoal is a significant tidal flat and underwater feature located in the Delaware River, just above the mouth of Poquessing Creek on the Pennsylvania side. This area is part of the larger Delaware Bay and River estuary system, characterized by brackish water influenced by significant tidal movement. The shoal itself is a partly submerged flat, creating a distinct shallow-water environment adjacent to deeper navigational channels. This structure, combined with the tidal flow, makes it a productive area for inshore saltwater angling targeting species that utilize these transitional habitats.