Hi John and thanks for the picture and question about your large black ants. Well, yes... you need to be concerned. If you see 2 there are probably more and you need a professional to find and treat the colony before it does major damage to your house. These are carpenter ants and I'll attach a site with more information including how to find a pest control company.
https://solvepestproblems.oregonstate.edu/insects-spiders/carptenter-ants
Good job noticing the critters and good luck with the treatment!