Clarication on the Carter House (if the name isn't enough). Fountain Branch Carter completed building his home in 1830. The house and grounds, which served as a Federal command post before the battle and as a hospital after, are today preserved on ten acres. In this evening battle lasting only five hours, 6,000 Confederate soldiers, including six generals, were killed. More than one thousand bullet holes are still visible from the battle.
According to offthebeatenpagetravel.com (picture toward the end of the article) and eu.tennessean.com, that would be the farm office of the Carter House in Franklin, Tennessee. possumjimandelizabeth.com IMO supports that as the first pic says "near Carter House". The Insiders' Guide® to Nashville by Jackie Sheckler Finch, p. 203, states that "the Carter House [is] considered to have the most bullet-damaged building from the Civil War still standing anywhere." americanheritage.com, however, says that the Carter House is the most bullet-damaged building.
Considering that the Carter House is a farm with several buildings, not only one (main) house, and that the question asks "what am I", I am going with the farm office of the Carter House in Franklin, Tennessee.