Ms. Brown dances in “Lateral Pass” (1985). (Mark Hanauer/Trisha Brown Dance Company )

Trisha Brown, a choreographer whose edgy innovations — including performances on rooftops and sideways on walls — were credited with revolutionizing dance in the 20th century, died March 18 at an assisted-living center in San Antonio. She was 80.

She had vascular dementia, said Barbara Dufty, the executive director of the Trisha Brown Dance Company in New York.

Ms. Brown was a standard-bearer of postmodern dance, an art form that favored natural, everyday movement over the more formal, stylized motions glorified in ballet and other genres.

She envisioned dances to be performed in un­or­tho­dox venues, such as parking lots, and without sound. Not until well into her career did she create choreography for the traditional stage or with accompaniment.

“I like to know the limits of my space, and I like to push it,” Ms. Brown told the Los Angeles Times in 1997. “I like to go to boundaries and stand on them — breach them.”

A 2010 photo of “Floor of the Forest” (1970) in Brazil. (Carrie Brown/Trisha Brown Dance Company)

The effect of her relentless experimentation was to enlarge the definition of dance. She was a recipient of a MacArthur fellowship, colloquially known as a “genius grant,” in 1991 and was widely hailed by fellow dancers and dance critics as a visionary.

Ms. Brown established herself as a choreographer in the New York dance scene of the early 1960s and founded her eponymous dance company in 1970. The same year, she debuted “Man Walking Down the Side of a Building” — “a glorious breach of the usual definition of choreography,” she said to the Houston Chronicle, in which a dancer used a harness and rope system to perambulate along a vertical plane.

Another significant early work, “Roof Piece” (1971), featured dancers clad in red, performing atop the rooftops of New York’s Soho neighborhood in a scene equal parts eccentric, provocative and, in its own way, beautiful.

In “Glacial Decoy” (1979), Ms. Brown’s first work for the traditional stage, dancers moved about in what to some viewers might have seemed a mysterious trance. That dance, like many of Ms. Brown’s early works, was performed in silence. She later incorporated music — in part, she quipped, because she grew weary of hearing the coughing of audience members over the tapping of her dancers’ feet.

Ms. Brown had notable collaborations with artist Robert Rauschenberg and composer Laurie Anderson, with whom she created her dance “Set and Reset” (1983).

“This is a dance whose currents you feel kinesthetically as you watch; you feel it on your very skin, like running water,” New York Times dance critic Alastair Macaulay wrote in 2013. “Its translucent pajama costumes and its decor of screens playing black-and-white newsreel-like collage are among the greatest achievements of Rauschenberg; its score by Ms. Anderson is insidious. Ms. Brown’s dances enriched the era in which we lived. ‘Set and Reset’ is a dance I would want the whole world to see.”

Patricia Ann Brown was born in Aberdeen, Wash., on Nov. 25, 1936. When she was a child and her parents enrolled her in music lessons, she insisted that she study dance as well.

A 2010 photo of “Set and Reset” (1983). (Julieta Cervantes/Trisha Brown Dance Company)

She credited an early teacher with exposing her to forms as varied as tap, ballet, jazz and acrobatics. She furthered her study of ballet at Mills College, in Oakland, Calif., where she graduated in 1958. As a university student, and in the early years of her career, she trained under choreographers José Limón, Merce Cunningham and Anna Halprin.

In New York, Ms. Brown helped found Judson Dance Theater and performed with the improvisational group Grand Union before founding her company. She took to dancing in such unusual locales as parking lots, she said, because she initially had no theater to perform in.

During the 1970s, she choreographed dances on the theme of “Accumulation,” In those works, dancers formed routines by adding one move at a time, repeating the entire sequence with each addition.

Ms. Brown retired from choreography because of ill health. Her final work, premiered in 2011, was titled “I’m Going to Toss My Arms — If You Catch Them They’re Yours.”

Her first marriage, to dancer Joseph Schlichter, ended in divorce. Her second husband, Burt Barr, an artist whom she married in 2005, died in 2016. Survivors include a son from her first marriage, Adam Brown of Kapaa, Hawaii; a brother; a sister; and four grandchildren.

“I’m always trying to press forward and outward the boundary of what I know,” Ms. Brown once told The Washington Post. “I’m trying to expand my vocabulary of movement, and trying to leave myself open to impulse and accident. I don’t want ever to be just automatically making a fixed product.”