Maps showing explorers' routes, trails & early roads in the United States :  An annotated list / 
Comp. by R.S. Ladd. 
 - Washington :  Libr. of Congress,  1962. 
 - VI, 137 p. :  1 map ;  26 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Maps<br/>Trails--United States