These ants are among the largest in Minnesota, but size alone isn't enough to determine if they are carpenter ants as the smallest workers are only 3/16" long. Most carpenter ants we see are larger; up to 1/2" in size. They are generally black, although some are reddish brown.
Found generally in forested areas and buildings, where they live in nests excavated in wood.
These insects live in wood, either tree trunks or wooden structures where they hollow out galleries for a nest. They do not eat wood, like termites, but in sufficient numbers and given time they can cause structural issues with wooden buildings. The photo above was taken of a carpenter ant I found in our house. It is cleaning its antennae in this photo.