Here are the top twenty most-published Christmas hymns, based on data from the Dictionary of North American Hymnology. The number following each hymn is the number of hymnals in which it was published in North America before 1979, according to the DNAH, plus about 40 hymnals published since then.

1. Joy to the world! (1,387)
2. Hark! the herald angels sing (974)

A shiny new feature has just been added to Hymnary's search capabilities: a new tool for searching tunes by their melody. If you've ever tried searching by incipit, you know that it is far from easy - you have to convert notes to numbers in your head, and if you drop a note or misremember a pitch, nothing comes up. This new tool aims to take the pain out of the process by letting you input your search melody directly in musical notation, with no mental gymnastics required! (Read all about how to use it here).

The Dictionary of North American Hymnology is online! Cheers! However, it may be incomplete or incorrect, and not all features may be working optimally, until we've had a chance to test it more thoroughly. You can read more about the DNAH project.