The nest you see is likely that of either European Hornets or Bald Faced Hornets. As long as no one disturbs the nest, there is no danger. These insects are not usually aggressive, but they will defend the nest. European hornets feed/fly both day and night, so you may see them around your porch light looking for moths and other insects to predate. These are the only true hornets in our country.
The Bald Faced Hornet is actually a wasp. Both species are excellent predator insects, although European hornets can be a nuisance when they attack a honey bee hive.
The colony of each of these insects will die at the first freeze and the nest will not be re-used next year. Only the queen of each colony will survive. She will find a sheltered place to overwinter and establish a new colony in the spring at a different location.
Many people collect the empty nests and slice them open carefully to display the intricate chambers inside.