The Great Pacific garbage patch, also described as the Pacific trash vortex, is a gyre of marine debris particles in the central North Pacific Ocean. It is located roughly from 135°W to 155°W and 35°N to 42°N. The collection of plastic, floating trash halfway between Hawaii and California extends over an indeterminate area of widely varying range depending on the degree of plastic concentration used to define it.

The patch is characterized by exceptionally high relative pelagic concentrations of plastic, chemical sludge and other debris that have been trapped by the currents of the North Pacific Gyre. Despite the common public image of islands of floating rubbish, its low density (4 particles per cubic meter) prevents detection by satellite imagery, or even by casual boaters or divers in the area. It consists primarily of an increase in suspended, often microscopic, particles in the upper water column.

The patch is not easily seen from the sky, because the plastic is dispersed over a large area. Researchers from The Ocean Cleanup project claimed that the patch covers 1.6 million square kilometers. The plastic concentration is estimated to be up to 100 kilograms per square kilometer in the center, going down to 10 kilograms per square kilometer in the outer parts of the patch. An estimated 80,000 metric tons of plastic inhabit the patch, totaling 1.8 trillion pieces. 92% of the mass in the patch comes from objects larger than 0.5 centimeters.

Research indicates that the patch is rapidly accumulating.

A similar patch of floating plastic debris is found in the Atlantic Ocean, called the North Atlantic garbage patch.