Wilbur H. Siebert, The Underground Railroad from Slavery to Freedom
(New York 1898; reprinted 1967) contains an appendix listing by county
and city or town individuals said to have been associated with the Under
Ground Rail Road.  This data could be mapped to indicate the distribution
of "agents" or other persons listed by Siebert, but that would not
constitute a map of routes, let alone a complete map of UGRR sites.

A general railroad and highway map of New York before the Civil War
would be the fairest, fullest map of the UGRR.  Surely it would have been
beneficial for the escaping slaves NOT to have followed prescribed
routes!

Jim Folts
New York State Archives