Baseball cards were included in boxes of Cracker Jack in 1914 and 1915.
Notes on verification
Confirmed by multiple independent hobby/research sources including SABR, PSA CardFacts, and CardboardConnection, all agreeing on distribution details for 1914 and 1915.
Sources
- Would Baseball have Become America's National Pastime Without ... (smithsonianmag.com)
- https://sabr.org/journal/article/1914-15-cracker-jack-baseball-cards-2/ (sabr.org)
- https://www.psacard.com/cardfacts/baseball-cards/1915-cracker-jack/130 (psacard.com)
- https://www.cardboardconnection.com/1915-cracker-jack-baseball-cards (cardboardconnection.com)