Which spiral arm of the Milky Way is located between the Sun and the Galactic Center?

The Sagittarius Arm is the Milky Way spiral arm located between the Sun and the Galactic Center.

Earth and the Solar System sit in the Orion Arm, a smaller spur positioned between the Sagittarius–Carina Arm on the inward side and the Perseus Arm on the outward side. When astronomers look from Earth toward the Galactic Center, they look through the Sagittarius Arm before reaching the galaxy’s central bulge.

The arm is named for the constellation Sagittarius, which lies in the same general direction on the sky. It contains many bright star-forming regions, including the Lagoon Nebula and the Eagle Nebula, as well as dense clouds of gas and dust. Those clouds also contribute to the dark band known as the Great Rift, which obscures much of the Milky Way’s central region in visible light.

Modern surveys often call it the Carina–Sagittarius Arm because the structure continues into the southern-sky constellation Carina. Different maps may classify it as a major or minor arm, but its location inward from the Orion Arm is the same.