The group, which crossed the Rio Grande River on rafts earlier, began walking just around sunrise.
They encountered U.S. Customs and Border Protection agents who provided them with large plastic bags to hold their belongings and arranged transportation to the wall.
Drone video also showed migrants walking as U.S. Customs and Border Protection agents drove behind them.
U.S. President Joe Biden Biden has defended his handling of rising migration at the U.S.-Mexico border and his decision to roll back immigration policies of his Republican predecessor.
The Trump-era order allows border agents to rapidly expel migrants without giving them a chance to claim asylum, but it has angered civil rights groups, who say it is illegal.
The number of migrants caught at the border has climbed sharply in recent weeks, thrusting Biden into an emerging humanitarian and political crisis a little more than two months after he took office.
The Biden administration has struggled to house the children arriving without a parent or legal guardian, which has left them stuck in crowded border facilities for days.