Information on the largest TSP instances solved to date can be found by following the links given below.

pla85900
85,900 Locations in a VLSI Application
Solved in 2006
Sweden Germany
24,978 Cities in Sweden
Solved in 2004
15,112 Cities in Germany
Solved in 2001

usa13509
A tour of 13,509 US cities. Solved in 1998.
rl11849
A 11,849-hold drilling problem for a printed circuit board.
pla7397
A 7,397-city problem arising in an application at AT&T.
rl5915
A 5,915-hole drilling problem for a printed circuit board.