Mexican authorities discovered an incomplete cross-border tunnel near Jacume , Baja California , Mexico.

The tunnel was found by Mexico State Police , Policia Estatal Preventiva and Mexican military forces while conducting an operation near Jacume on September 19, 2018. The tunnel was located in a residence about 220 feet from the U.S. / Mexico International boundary. The tunnel was turned over to the Attorney General of Mexico the next day and a warrant was issued to search the house and the tunnel. Mexican authorities invited the U.S. Border Patrol's Western Corridor Tunnel Interdiction Group ( WCTIG ) to enter the tunnel from the Jacume entrance so they could map the excavation and see if there was an exit point on the U.S. side of the border.

On October 4, 2018 , Homeland Security Investigations, Drug Enforcement Administration Border Patrol agents determined that the tunnel had a shaft that was 31 feet deep , with a total length of 627 feet with slightly more than half of that in the United States. An exit shaft was located. It went approximately 15 feet towards the surface but did not break the surface. Agents reported a solar panel system was used to run lighting and ventilation systems in the tunnel. There were also two sump pump systems in the tunnel as well as a rail system that ran the entire length of the tunnel.