What is the innermost named ring of Saturn?

The D ring is Saturn's innermost named ring.

The D ring is extremely faint and lies closest to Saturn, extending inward toward the planet's upper atmosphere. Its listed radial range is approximately 66,900 to 76,517 kilometres from Saturn's centre. Compared with the bright A and B rings, the D ring is difficult to see and is made largely of fine, dusty particles and water ice.

Voyager 1 confirmed the D ring in 1980 and identified three ringlets within it, designated D68, D72 and D73. D68 is the discrete ringlet nearest Saturn. Later observations by the Cassini spacecraft showed that parts of the D ring had broadened and shifted planetward.

The common mistake is starting with the prominent rings visible in amateur telescopes. The C ring is the innermost of Saturn's major bright rings, but the D ring lies inside it. The E and G rings are much farther out, while the A ring is one of the main outer bright rings.