The interior of Lassell has been flooded and resurfaced by lava, leaving a nearly flat surface with a low remaining outer rim. The surface has a low albedo, giving the interior a dark appearance. The surviving outer wall is generally circular but with a somewhat polygonal shape.

To the east-northeast is a circular, bowl-shaped crater designated Lassell B. This formation has a higher albedo than its surroundings and so appears relatively bright, especially at high sun angles.

The tiny crater Lassell D is located to the west-northwest of Lassell, about halfway to the ruined crater Guericke. This craterlet is surrounded by a patch of high-albedo surface, and is an example of a prominent lunar bright patch. The light hue is thought to be an indication of recent formation, at least in lunar geological terms.

To the west of Lassell, at coordinates 14.65°S, 350.96°E is a small highland area called the Lassell Massif, which has a reddish color relative to the surrounding mare.^[2]

The massif was created by series of eruptions of viscous silicic lavas starting 4.07^+0.05
_−0.08 billion years ago. Its surface is suspected to be partially buried by ejecta from Copernicus crater. The southern domes Lassell G and Lassell K have most silica-rich composition and feature a caldera-like depressions on tops.^[3]

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Lassell.

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• Lassell at The Moon Wiki
• Wood, Chuck (February 13, 2007). "New Observations of a Well-Known Area". Lunar Photo of the Day. Archived from the original on June 14, 2011.
• Wood, Chuck (January 31, 2010). "Spotted Moon". Lunar Photo of the Day.