Connecticut
In Connecticut, trade names are filed in the town where business is to be conducted or transacted. There is no state-level trade name registration. Foreign businesses with an office in Connecticut should file in the town where that office is located. If the business has multiple offices or locations, choose the one that is considered to be the principal Connecticut location. If the business has no other connections to Connecticut, select the town where the resident agent is located.
Trade name registration is required for LLCs, corporations, and other entities that desire a "doing business as" name. General partnerships that desire a business name that does not include any surnames of the owners and sole proprietorships that desire a business name that does not include their surname are also required to register a trade name. Trade names must be renewed every 5-years.