When migrants arrive in Tijuana, they add their name to a list, which has been managed by a series of volunteers who are waiting their turn to speak with CBP.

13,000 immigrants are currently on waiting lists to request asylum between eight cities of the US-Mexico border, according to the Associated Press.

The backlog occurring at every one of these ports tasks those crossing legally into the U.S. with anywhere from one to five months wait time before their asylum process can begin.

In this system of metering, U.S. Customs and Border Protection (CBP) agents alert Mexican authorities or liaisons as to how many asylum applications they can process that day.

At some ports, these customs agents are in short supply. The rigorous screening process to become a customs agent includes an eight-hour polygraph test, which two out of three applicants fail.

There are 23,477 officers to man all pedestrian, vehicle, and freight ports of entry, according to the CBP statistics released in March.

At the San Ysidro port between Tijuana and San Diego, a larger staff of customs agents can handle up to 80 applicants each day. Still, 4,800 people are in line to reach this stage and open their asylum cases, currently the longest line of anywhere on this border.

(A group of migrants wait in a huddle after being called forth by number to speak with U.S. Customs and Border Protection officials at the San Ysidro port on May 7, 2019. Photo by Jenna Mulligan.)

When migrants arrive in Tijuana, they add their name to a list, which has been managed by a series of volunteers who are waiting their turn to speak with CBP. This week, numbers hovering around 2,500 are being called. Groups and families sit near to El Chaparral, an entrance of the San Ysidro crossing, to listen for their turn.

Metering began in this city in 2006, when the Obama administration tried to control the swell of Haitian asylum seekers arriving at the San Ysidro port.

The metering system in San Luis de Colorado, a town south of Yuma, is also run by a migrant awaiting admission. Like in Tijuana, they will train another to take over the organization of the waitlist when their number is near.

But in San Luis, some days pass without a single person called forward to the U.S. CBP. There are about 900 on the list, but only 15 families are permitted to camp out near the border and the vehicle traffic passing by. The others rely on shelters, churches, and boarding houses for the duration of their wait.

In Ciudad Juárez, across the border from El Paso, Texas, the Chihuahua state government has taken over the metering system from Casa Migrante, a local shelter. They input names and assign numbers through a digital system now, and have created a closed Facebook group that is updated twice each day with current numbers that the U.S. is accepting. Currently, 4,500 remain on this list, according to the AP.

(The plaza south of the Nogales port of entry, where migrants wait alongside those who cross regularly between Sonora and Arizona. Photo by Jenna Mulligan.)

In smaller border cities such as Piedras Negras and Nogales, local volunteers control the list of names, and reach out by phone to those nearing their turn. Far fewer applicants are accepted weekly at these ports. Still, some asylum-seekers choose to wait in these smaller towns because of their safer reputations.