Gerhard Reinelt's library TSPLIB

http://www.iwr.uni-heidelberg.de/groups/comopt/software/TSPLIB95/

includes 110 instances of the symmetric traveling salesman problem, of which 106 have been solved. (The four remaining unsolved instances have 14,051 cities, 18,512 cities, 33,810 cities, and 85,900 cities.)

TSPLIB instance usa13509 (13,509 cities in the U.S.A.):

Solved on May 8, 1998 



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