NATIONAL DACHSHUND DAY - JUNE 21ST The Dachshund may rank 10th on the American Kennel Club’s annual list of most popular dogs, but these small dogs with larger-than-life personalities hold the number one spot in the heart of anyone who has been fortunate enough to have welcomed a dachshund into their life. WHY THE 21ST? June 21st is celebrated as the National Dachshund Day because it’s the longest day of the year in the Northern Hemisphere. Since Dachshunds are the longest dog breed proportional to its size, it stands to reason that we’d celebrate these dogs on June 21st.