Vietnam Conflict

Here are some good sites for finding all kinds of maps including thematic and topical one.

American Units in Vietnam

 

(source)

Ho Chi Minh Trail

(source)

Locating Maps

Here are some great pages that will help you locate maps including: country, military, thematic and topical.

Tet Offensive - 1968

 

(source

Gulf of Tonkin

(source)

Easter Offensive - March-May 1972

(source)