By 1855, 16 states celebrated Thanksgiving (14 on the fourth Thursday of November, and two on the third). However, it was not until 1863 that Abraham Lincoln established the regular tradition of observing days of national thanksgiving.
Up to 1855, 16 states observed Thanksgiving (14 on the fourth Thursday of November, and two on the third). Nonetheless, it wasn't until 1863 that Abraham Lincoln instituted an annual practice for marking days of national thanksgiving.