Web Author's Notes:
The 16th Ohio Volunteer Infantry was the first Union regiment to actually cross into Confederate territory, ultimately participating in the first official land battle of the war at Philippi, (West) Virginia, on June 3, 1861. This crossing took place from Bellaire, Ohio, to Benwood, (West) Virginia, and points east and south, on Monday, May 27, 1861.

The following article is from the Ashtabula Weekly Telegraph, published June 1, 1861, briefly describing the first movement of Union troops into Confederate territory, including the 16th Ohio.