Terminalia was an ancient Roman festival in honor of the god Terminus, who presided over boundaries. His statue was merely a stone or post stuck in the ground to distinguish between properties. The god Terminus was not the original cause for the celebration of the Terminalia. He was in fact created, an example of the open-minded thinking of Roman religion and its animistic and numinal character, to serve as a god for the existing Terminalia and not vice versa. On the festival the two owners of adjacent property crowned the statue with garlands and raised a rude altar, on which they offered up some corn, honeycombs, and wine, and sacrificed a lamb or a sucking pig. They concluded with singing the praises of the god.
Ovid refers to the sacrifice of a sheep on the day of the Terminalia at the sixth milestone from Rome along the Via Laurentina; it is likely this was thought to have marked the boundary between the early Romans and their neighbors in Laurentum. Also, a stone or altar of Terminus was located in the Temple of Jupiter Optimus Maximus on Rome's Capitoline Hill. Because of a belief that this stone had to be exposed to the sky, there was a small hole in the ceiling directly above it.
The festival of the Terminalia was celebrated a. d. VII. Kal. Mart., or the 23d of February on the day before the Regifugium. The Terminalia was celebrated on the last day of the old Roman year, whence some derive its name. We know that February was the last month of the Roman year, and that when the intercalary month Mercedonius was added, the last five days of February were added to the intercalary month, making the 23d of February the last day of the year.