Lat: 38.0°N, Long: 29.2°E, Diam: 384 km, Depth: 2.49 km, Rükl: 14
Clementine The large circular crater at bottom middle is Posidonius. Lacus Somniorum consists of the two patches of relatively light mare above it, to the left and the right. The darker mare to the lower left is part of Mare Serenitatis. The finger of dark mare intruding into Lacus Somniorum from the left (to the northwest of Posidonius) falls in a region where the IAU definitions of Lacus Somniorum and Mare Serenitatis overlap, at least based on their stated positions and diameters.
- Depth data from Kurt Fisher database
- Cherrington, 1969: 2.49 km
- Mare area of 47,300 km^2 according to measurements by Jim Whitford-Stark.
- "Lake of Dreams".
- The eastern part was called Lacus Scientiae by Van Langren.
- The part between craters Maury, Maury A (Lamech's "Touchet"), and Hall, is called Lacus Locusta, or Lobster Lake by the dedicated moon-observer RonB(ee).
- Erroneously printed as "LACUS SOMNORIUM" on page 29 (chart 8) of Chuck Wood's and Maurice Collins's 21st Century Atlas of the Moon (2012).- DannyCaes Jan 21, 2013