M'kemas III: Planet located in Tzenkethi territory.
M-113: -Former home of the Salt Vampire.
       -Planet studied by archaeologist Doctor Robert Crater
M24 Alpha : Star system that contained planet Triskelion.
Mab-Bu VI: -Planet with class M moon where disembodied alien criminals lived.
           -Crash site of U.S.S. Essex NCC-173.
MacPherson Nebula: Supernova remnant used as a source of vertion particles for the emergent 
                   life-form which occupied U.S.S. Enterprise NCC-1701-D.
Makus III: Planet where U.S.S. Enterprise NCC-1701 was to deliver medical supplies.
Malaya IV: Planet where Paul Hickman had a physical exam.
Malcor III: Planet where Commander William Thomas Riker conducted covert sociological studies.
Malkus IX: Planet whose inhabitants developed writing before sign language.
Malurian system: System completely "sterilized" by Nomad.
Manark IV: Home of the Sandbats.
Manu III: Planet whose government used proximity detectors.
Manzar Colony: -United Federation of Planets settlement.
               -A new defense perimeter was installed there in 2375 by Lieutenant
                Commander Worf.
Mar Oscura: A dark-matter nebula located in Federation space.
Maranga IV: Lieutenant Worf attended the Klingon Kot'baval Festival there in 2370.
Marcos XII: Planet chosen by the evil Gorgan to conquer and control.
Marejaretus VI: Homeworld to the Ooolans.
Mariah IV: Planet visited by a Valerian vessel when delivering supplies.
Marijne VII: Gas giant planet.
Mariposa: Planet settled by human colonists from S.S. Mariposa.
Marlonia: Planet visited by some of the crew of U.S.S. Enterprise NCC-1701-D in 2369.
Mars: -Fourth planet in Sol system.
      -Location of Utopia Planitia Fleet Yards.
Martian Colonies: -United Fedration of Planets settlements on Mars.
                  -Important legal declarations on human rights were written there.
Marva IV: Class M planet locted in the Badlands.
Mataline II: Planet where Neela Daren purchased a flexible piano keyboard.
Mavala IV: Planet where Noonien Soong married Juliana O'Donnel.
Maxia Zeta Star system: Star system where the Battle of Maxia was fought.
McAllister C-5 Nebula: Nebula located 7 light-years inside Cardassian space.
Meezan IV: Planet where Lieutenant Doctor Julian Subatoi Bashir attended a burn treatment
           conference.
Mekorda Sector: Area of space where U.S.S. Enterprise NCC-1701-D weathered a magnascopic storm.
Meldrar I: Planet.
Meles II: Suggested port of call for Professor Moriarty.
Melina II: Planet visited by Tarmin and his group of telepathic historians.
Melnos IV: Planet where Neela Daren led a team to study a plasma geyser.
Melona IV: Planet attacked by the Crystalline Entity in 2368.
Meltasion asteroid belt: Asteroid belt through which U.S.S. Enterprise NCC-1701-D was forced 
                         to tow a contaminated barge full of radioactive waste.
Memory Alpha: -Planetoid.
              -Location of a Federation library.
Mempa Sector: Star system in Klingon space where Chancellor Gowron suffered a major defeat 
              during the Klingon civil war.
Merak II: -Planet ravaged by a botanical plague in 2269.
          -Quark said the inhabitants of Merak II made the best scanners.
Mercury: -First planet in the Sol system.
         -Orbitibg Sol at a distance of some 58 milliion kilometers.
         -Dayside temperatures to 430 degrees Celcius.
         -Inhospitable to unprotected humanoid life.
Mericor system: -Planetary system.
                -Crash site of U.S.S. Denver NCC-54927 after the ship struck a gravitic mine 
                 in 2368.
Meridian: Planet that undergoes dimensional shifts every 60 years.
Merik III: Planet in the Gamma Quadrant.
Merkoria Quasar: Phenomenon under study by U.S.S. Enterprise NCC-1701-D in 2370.
Micro-wormhole: A wormhole whose singularity has mostly dissipated, leaving an extremely narrow
                passageway through subspace.
Midos V: Planet where Doctor Roger Korby planned to begin manufacturing androids.
Milika III: Planet where Jean-Luc Picard led an away team to rescue an ambassador.
Mikah: Planet in the Delta Quadrant.
Mimas: -Moon of Saturn.
       -Nova Squadron was evacuated from Mimas.
Minara II: Planet used by the Vians.
Minaran Star system: -Planetary system.
                     -Formerly it had several inhabited worlds.
                     -Star, Minara, went nova in 2268.
Minos: Planet whose inhabitants sold weapons during the Erselrope Wars.
Minos Korva: Federation planet.
Mintaka III: -Planet.
             -Site of Federation anthropological study of a proto-Vulcan culture.
Mira system: Location of Dytallix B.
Miramanee's planet: -Planet.
                    -Home to native American Indians transplanted from Earth.
Miridian VI: Planet where Barash said he'd been captured by Romulans.
Mislen: Planet orbiting a yellow dwarf star in the Delta Quadrant.
Mithren: Planet in the Delta Quadrant.
Mizar II: Homeworld to the Mizarians.
Moab IV: -Inhospitable planet.
         -Site of genetically-engineered colony.
Modean system: Star system that Geordi LaForge visited as a child.
Monac IV: -Planet.
          -Site of Dominion orbital shipyards which were destroyed in 2375.
Moon: -Planetoid.
      -Earth's only natural satellite.
Mordan IV: Planet plunged into a 40-year cvil war after outside interference by Starfleet
           Captain Mark Jameson.
Morikin VII: Planet where Cadet Jean-Luc Picard was assigned for training.
Moriya system: Star system in the Badlands.
Morska: Klingon planet on which is located a subspace monitoring outpost.
Moselina system: -Star system.
                 -Destination of U.S.S. Enterprise NCC-1701-D when it was invaded by nitrium 
                  metal parasites.
Mudd: Class K planet inhabited by a group of androids led by Norman.
Mudor V: Planet from which U.S.S. Enterprise NCC-1701-D departed before striking a series of 
         quantum filaments.
Murasaki 312: -Quasar-like formation near planet Taurus II.
              -Investigated by Shuttlecraft Galileo in 2266.
              -Investigated by U.S.S. Enterprise NCC-1701-D in 2367.
Mutara Nebula: -Interstellar dust cloud in the Mutara Sector.
               -Transformed into the Genesis Planet.
Myrmidon: Planet where archaeologist Vash was wanted for theft.