The phrase "legally designated" is correct and usable in written English.
It indicates that something has been assigned a specific legal status. You can use it when referring to official documents, people, decisions, etc. For example: "The board of directors was legally designated to make the final decision."
In fact, Christian moneylenders were sometimes legally designated as temporary Jews when they lent money to English and French kings.
One can easily foresee challenges to the Law of Return, which grants immediate citizenship to any legally designated Jew.
Nearly all were prepackaged, legally designated Grade C munitions, limited to five hundred grams of explosive per unit.
Although carriages informally gather in several areas on Central Park South, no formal hack stands have been legally designated.
My understanding is that, as of this spring, there were approximately forty legally designated, fugitive high-value targets at the top of the wanted-list system.
The group represents eight sanctuaries in the United States and Canada, including the legally designated national chimpanzee sanctuary, known as Chimp Haven, in Louisiana.
This includes legally designating someone to make health care and financial decisions for the affected person when he or she can't.
The highest lead levels found by the Flint researchers at any point came to 13,000 parts per billion — far beyond what the EPA would legally designate "toxic waste". Testing conducted by the city, on the other hand, appeared to show lead levels within reasonable limits.
The term victim legally designates an individual who has suffered a human rights violation and who is subsequently entitled to protection and compensation.
Don Schmitz, the lobbyist the city retained as its advocate to the Coastal Commission, gave the council an optimistic yet frank assessment of the commission's recent reaction to the first step in the port plan process: a proposed amendment to the California Coastal Act to legally designate Newport Harbor as a port.
The Indian Forest Act of 1927 legally designates government forests into three categories that offer graduated degrees of protection.
