Mexico's National Migration Institute said 969 migrants from Honduras, El Salvador, Guatemala and Nicaragua crossed into Ciudad Hidalgo just days after new U.S.-bound caravans of people set off from Central America.
Caravans from Central America have inflamed the debate over U.S. immigration policy, with U.S. President Donald Trump using the migrants to try to secure backing for his plan to build a border wall on the frontier with Mexico.
Mexican President Andres Manuel Lopez Obrador is pursuing a "humanitarian" approach to the problem, vowing to stem the flow of people by finding jobs for the migrants. In exchange, he wants Trump to help spur economic development in the region.
The U.S. government has been partially shut down for more than three weeks as Democrats resist Trump's demand that Congress provide $5.7 billion to fund his planned wall.
Mexican officials put wrist bands on the migrants as they entered the country to monitor the flow of people. The bands must be kept until the migrants register with authorities.
Once registered, migrants who met the requirements to stay would be issued humanitarian visas, allowing them to work in Mexico or continue to the U.S. border, said Ana Laura Martinez de Lara, director general of migratory control and verification.
Those who entered Mexico at the official border crossing had done so in a "very orderly" and respectful manner, in contrast to clashes that took place at the frontier in October when a larger caravan began crossing from Guatemala, she said.
Some of the migrants expected to stay in Mexico to find work but it was too early to say how many, she said.
Martinez de Lara said approximately 700 people were still waiting to cross into Mexico from Tecun Uman on the Guatemalan side of the border. She could not say if any people had tried to cross into Mexico illegally.
Mexico's government said Foreign Minister Marcelo Ebrard planned to meet U.S. Secretary of State Mike Pompeo soon for talks on their efforts to address the migration challenge. No date was yet set for the talks, a ministry spokeswoman said.