Any proper town in Latin America has a church facing a plaza — except the towns of the Sierra Norte region of Mexico, where Jorge Santiago is from.

“In my part of the Sierra, the basketball courts are like the zócalo in the colonial city,” Mr. Santiago said, using a Mexican word for “plaza.” “It’s really the most important part of the town. A respectable town has a church, and a basketball court in front of the church.”

Call it the postcolonial era — for the last 80 years, the people who live in this mountainous part of Mexico, in the state of Oaxaca, have been crazy about basketball. Introduced to the region by a president who wanted to unite, or perhaps distract, the various indigenous groups, the sport has taken root and become more popular than soccer. It occupies a physical place of honor, with the courts built on the few flat stretches of any town.

Jorge Santiago

“Basketball was really important to me,” Mr. Santiago said of his childhood in Guelatao de Juárez. “There was nothing to do. The only place to get some satisfaction was on the basketball court. I really believe it was one of the only things that offered an opportunity for the people of the Sierra to be different from the rest of Mexico.”

Just how different is evident in “Identity at Play.” The series explores basketball and the attendant rituals that have come to surround hoop culture in the Sierra, where basketball tournaments are intertwined with local customs and celebrations. As unlikely as it might sound, the sport has helped foster a sense of community.

Not that Mr. Santiago knew that growing up. In his town, there were 300 people and two television stations, one of which carried N.B.A. games. He left to study business in Mexico City, but returned to Oaxaca after graduation. He had already begun taking photographs, thanks to a workshop he had participated in as a teenager.

At first, Mr. Santiago was interested in documenting migration. While researching that topic, he came across “True Tales From Another Mexico” by Sam Quinones, which had a story about an Oaxaca native who started a “basketball movement” in Los Angeles.

“That’s when I realized how important basketball is when you don’t have it,” he said.

Jorge Santiago

When he first started taking pictures, he concentrated too much on the sport itself. It was not until he moved to Pittsburgh, where his wife was studying, that he realized he needed to place the sport in the region’s cultural context.

“People will sacrifice the flattest space in a town to build a basketball court,” he said. “Then they end up using it just like a plaza, like a social place. It’s not only the space where sport happens. There are weddings there. All the dances take place on the court. There are political meetings there.”

Tournaments are held in dozens of villages, timed to the feast days of the town’s patron saint. That adds yet another dimension to the sport’s significance, with political and religious beliefs coming together.

“There is one photo where they are sacrificing a bull at the same time they are cutting the ribbon for the court,” Mr. Santiago said. “It’s interesting how all these get combined in basketball.”

Players from different teams go from feast to feast, vying for prize money, which ranges from 15,000 to 40,000 pesos (about $1,100 to $3,000). The big event of the season is in Guelatao’s Copa Benito Juárez, named after the Mexican president who was born there, which attracts as many as 200 teams over a five-day period.

The prize money is often supplied by migrants from the area who now live in the United States. Many of them come back for the festivities, sometimes playing on courts whose color schemes mimic N.B.A. courts.

Mr. Santiago, who stopped playing basketball once he took up photography, is now following another aspect of migrant life.

“I’m doing a project on the houses built by migrants in their hometowns,” he said. “Most of them are abandoned. They start building the house after having been in the States a while. But most of them never come back.”

Jorge Santiago

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