Chatham Beach, also known locally as Erin Bay, is a significant coastal feature located on the southwestern peninsula of Trinidad, near the community of Chatham. The beach fronts the serene waters of the Gulf of Paria, offering views across to the Venezuelan coastline. This area is historically notable for its proximity to the Pitch Lake, one of the world's largest natural deposits of asphalt, which has influenced the region's development and ecology.

The coastline in this part of Trinidad is characterized by a mix of sandy stretches and mangrove ecosystems. The waters of Erin Bay are generally calm, sheltered by the geography of the gulf. The beach and its surrounding environment play a role in local fishing activities, supporting small-scale artisanal fisheries that are part of the area's traditional economy.

The region around Chatham Beach has archaeological importance, with evidence of pre-Columbian settlement and activity. Artifacts discovered in the vicinity indicate that indigenous peoples inhabited the area long before European contact, utilizing the marine and terrestrial resources available.

In terms of natural phenomena, the beach area is situated in a geologically active zone. Subsurface seepages of hydrocarbons and asphalt are not uncommon along this section of the coast, a terrestrial extension of the petroleum-rich formations that define southwestern Trinidad. The presence of these natural resources has shaped the industrial landscape of the surrounding wards.

Access to Chatham Beach is via the Southern Main Road, with the nearby town of Point Fortin serving as a major population center. The beach is less developed for tourism compared to other coasts on the island, retaining a more natural and local character. Visitors to the area often combine a trip to the iconic Pitch Lake with a stop at the nearby coastal viewpoints.

Conservation efforts in the wider Gulf of Paria focus on the protection of mangrove forests, which are vital for coastal protection and as nurseries for marine life. The environmental health of the bay is interconnected with the management of the industrial activities that dominate the region.