The elephants, from a game reserve run by nonprofit Big Game Parks, landed in Fort Worth, Texas, over the weekend aboard the cargo plane.
Before their departure from Swaziland, the giant animals were sedated and loaded onto crates for the 10-hour flight.
On arrival, five were transferred to the Dallas Zoo under police escort.
The remaining 12 are the newest residents of the Sedgwick County Zoo in Wichita, Kansas, and the Henry Doorly Zoo in Omaha, Nebraska, CNN reported.
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The zoos defended the transfer, saying the animals were set to be killed to make room for rhinos at the Swaziland facilities. The southern African country is also undergoing a drought.
"It escalated to a rescue mission last fall due to this state-of-emergency drought," said Gregg Hudson, president of Dallas Zoo.
In exchange for the elephants, the three US zoos will donate funds toward the rhino conservation efforts at Big Game Parks.
The elephants' ages range from 6 to 25.
Friends of Animals, which is based in Connecticut, said it had contested the move in court, and a hearing was scheduled for Thursday.
It accused the zoos of sneaking the elephants out of the African nation under the cover of darkness to avoid a lawsuit.
The Dallas Zoo described the accusation as "outlandish" and said the activist group Friday withdrew its request for a preliminary injunction.
The zoos have said the animals faced certain death at home and are better off in the United States.
He said the Dallas facilities are spacious enough for the giant animals to roam and forage.