A Body of Work for Historians : Dance: Chile’s troupe strives to promote its cultures, even when it has to reconstruct them first.

The Republic of Chile hugs the west coast of South America for about 2,650 miles, stretching inland only 250 miles at the max. At the southern tip of the continent, it throws its sovereignty another 2,300 miles west across the Pacific to mysterious Easter Island.

Within those borders are a variety of indigenous and Spanish-influenced cultures. It is the responsibility of Ballet Folklorico Nacional de Chile to “maintain and promote our culture and take our culture everywhere,” said Claudio Leroy, 27, a dancer in the company.

Leroy was speaking from El Paso, Tex., one of about 40 cities the company is dancing in on its first U.S. tour. (The troupe danced in Pasadena in 1990.) The tour, which began Sept. 20, includes a stop Thursday at the Irvine Barclay Theatre.

The troupe was founded in 1965 by a group of academics associated with the University of Chile and has been directed by Sergio Soto Ortiz since 1989. He had been technical director since 1970.

It is state funded and has the duty, Leroy said, of going out “at least every month to a different region in our country. Sometimes we perform in huge cities, with huge theaters and stages, and sometimes we perform in an open field in very small towns in the middle of the mountains.” While this contingent of 32 dancers and musicians is touring the United States, another team performs at home or tours South America. The full company numbers around 120, including costume makers and technical and support staff.

“We have almost 200 people applying for maybe two or three new posts each year,” Leroy said.

The training program can last four years. “We learn different dance techniques, the different styles of folk culture within our country, and work with researchers in the various regions.

Ortiz “wanted to establish the folk roots more firmly and minimize the show-business aspects. That’s why he’s always asking for experts who do research or people who are really close to the traditions in our country for advice.”

The dancer must realize that he “is there on stage not to dramatize himself, but to interpret the mood of the people who are living in a particular region.”

The regions the company will represent in Thursday’s program range from barren deserts in the north to the island cultures of the Chiloe Archipelago at the southern end tip of the continent. Plus Easter Island.

“It’s such a huge repertoire,” Leroy said. “Some of the dances have pre-Columbian origins. Some are from the new generation.”

While most of those cultures can be presented with confident authenticity, the choreography for the Easter Island segment must necessarily be “pretty conjectural,” Leroy said.

“The aboriginal population was decimated by contagious diseases or by internal wars,” Leroy said. “Fortunately, there are still some old people who are respected among the islanders, who have some knowledge of the past. We have worked with them for this suite.”

The overriding culture that Chileans identify with, however, is the ancient Mapuche culture that still thrives in southern Chile.

“That is the common root, the main root of Chilean culture,” Leroy said. “It is particular and unique. . . . They have a very deep philosophy of life, which is very close to the land. . . . they call themselves the ‘people of the land.’

“That’s the way they kept their language, their traditions. And they were the only ones who said to the [invading] Spanish: ‘You get to here, and then you go back. Not one step farther.’ They were not warriors but very good strategists, very intelligent.”

Ballet Folklorico Nacional de Chile will appear Thursday at 8 p.m. in the Irvine Barclay Theatre, 4242 Campus Drive, Irvine. $18 and $23. (714) 854-4646.