Bruce Murray Space Image Library
Map of all Mars landing sites as of November 2018
The map was assembled by Emily Lakdawalla from the following sources; any errors are hers. The base map is the Viking orbiter MDIM 2.1.
Mars 2: 45 S, 313 W (NSSDC)
Mars 3: 45 S, 158 W (TPS)
Mars 6: 23.90 S, 19.42 W (TPS)
Viking 1: 22.48 N, 49.97 W (NSSDC)
Mars Polar Lander: 76.57S, 165.2 E (read from map provided by HiRISE team)
Pathfinder: 19.33 N, 33.55 W (NSSDC)
Beagle 2: 10.6 N, 270 W (NSSDC)
Spirit: 14.571892 S, 175.47848 (Arvidson et al, JGR, 2006)
Opportunity: 1.9462 S, 354.4734 E (Squyres et al, JGR, 2006)
Phoenix: 68.218830 N, 234.250778 E (via press briefing)
Curiosity: 4.5895 S, 137.4417 E (Vasavada et al, JGR, 2014)
InSight: 4.502 N, 135.623 E (Golombek et al., LPSC, 2019)
ExoMars Schiaparelli: Near the Opportunity landing site.
ExoMars rover: 18.1N, 335.7E (read off this map from ESA, 2018)
Mars 2020 rover: 77.5945 E, 18.3628 N (landing site workshop)
The map was originally developed and posted in 2008; the 2008 version is available here, the 2014 version is available here, the 2015 version is available here, and the 2018 version is available here.