What is the name of the largest near-side lunar basin, often called the Ocean of Storms?

The largest near-side lunar expanse commonly called the Ocean of Storms is Oceanus Procellarum.

Oceanus Procellarum occupies much of the Moon’s western near side. It is the only lunar plain formally named an “Oceanus” rather than a mare, reflecting its exceptional size: it stretches more than 2,500 kilometers north to south and covers roughly 4 million square kilometers.

Its dark surface formed when ancient volcanic eruptions flooded the region with basaltic lava. The feature’s exact geological origin remains debated: scientists have proposed both a gigantic ancient impact and large-scale internal heating that produced fractures and volcanism. Modern descriptions often call it a vast plain rather than a clearly bounded impact basin.

The surrounding region contains familiar features such as Mare Imbrium, Mare Humorum, and Mare Nubium. Oceanus Procellarum also hosted several robotic landings, including Surveyor 1 and Surveyor 3, and Apollo 12 landed near Surveyor 3 in 1969.