From the passage provided, extract the date when the 34th Wisconsin Infantry Regiment was organized.

The 34th Wisconsin Infantry Regiment was a conscripted infantry regiment that served in the Union Army during the American Civil War. The 34th Wisconsin Infantry was composed of men drafted by state authorities under General Order No. 94. The regiment was organized at Madison, Wisconsin, and mustered into Federal service December 31, 1862.

The 34th Wisconsin Infantry Regiment was organized on December 31, 1862.