What was the name of the first American spacecraft to orbit the Moon?

The first American spacecraft to orbit the Moon was Lunar Orbiter 1.

Launched by NASA on August 10, 1966, Lunar Orbiter 1 entered lunar orbit four days later. Its main job was to photograph possible landing areas for the upcoming Apollo and Surveyor missions. The spacecraft’s images helped engineers assess terrain and identify safer sites for future landings.

Lunar Orbiter 1 carried a sophisticated film-based camera system that developed photographs aboard the spacecraft, scanned them, and transmitted the data to Earth. It photographed nine primary Apollo candidate sites, several secondary sites, and parts of the far side. It also returned the first photograph of Earth from the vicinity of the Moon.

A common mix-up is Apollo 8, which carried the first humans to lunar orbit in 1968. Another is Luna 10: it became the first spacecraft of any nation to orbit the Moon, in April 1966, several months before Lunar Orbiter 1. Lunar Orbiter 1 was specifically the first American lunar orbiter.