Vintage postmarked envelope with 'Always Use ZIP Code' slogan cancellation from South Bend, Indiana, dated March 1968

This envelope represents a piece of United States Postal Service history from the late 1960s, when the ZIP code system was still relatively new, having been introduced in 1963. The 'Always Use ZIP Code' slogan cancellation was part of a nationwide campaign to encourage Americans to adopt the new postal code system for more efficient mail delivery. The postmark from South Bend, Indiana, dated March 1968, places this item in the midst of the Vietnam War era and the tumultuous social changes of the 1960s. Vintage postal history items like this appeal to philatelists and postal history collectors who appreciate the evolution of mail systems and postal markings. These collectors value such items for their historical significance, the clarity of the postmark, and the presence of period-appropriate postal slogans. The item serves as a tangible connection to everyday life in 1960s America and the technological improvements in mail sorting and delivery that shaped modern postal services.