HOUSTON — In 1872, a group of African-American ministers and businessmen in Houston purchased 10 acres of land south of downtown, in the city’s predominantly black Third Ward neighborhood, and created Emancipation Park. Acquired for $800, the park was intended as a permanent site for the city’s annual Juneteenth celebration, which memorializes June 19, 1865, the day the Union Gen. Gordon Granger arrived in Galveston and belatedly put the Emancipation Proclamation into effect across Texas two and a half years after it became official.

On Saturday, Emancipation Park officially reopened — just in time for Juneteenth — after a three-year renovation. This time the price tag was $34 million, and amid the celebration, there was a concern that would have been hard to imagine in the past: Can Third Ward survive prosperity?

The area is one of the oldest and most culturally significant black neighborhoods in Houston, with a rich legacy of art, music, political activism and education. In the 1950s, the Eldorado Ballroom hosted B. B. King, Count Basie and Ray Charles. The historically black Texas Southern University was the center of the civil rights movement in Houston. More recently, Beyoncé Knowles, who grew up in Third Ward, has given the neighborhood a global profile by name-checking it in songs and featuring it in music videos.

Like many African-American communities across the country, Third Ward was hit hard by urban redevelopment, with Highway 288 slicing through the neighborhood’s western reaches. In the ’70s and ’80s, rising crime helped fuel an exodus of black families and businesses to Houston’s newly desegregated suburbs. Today, abandoned houses and vacant, overgrown lots are a common sight.

Along with the rest of Third Ward, Emancipation Park fell into decline over the past few decades. Weeds overtook the volleyball court and baseball field. The community center’s roof developed a leak. “You would not want to hang around after the sun went down,” said Ramon Manning, who has lived in Third Ward since the 1990s. “It was bad — drug dealing, prostitution, everything.”

Mr. Manning, the chairman of the Emancipation Park Conservancy, is one of the Houstonians responsible for reviving the park through a lavish renovation designed by Philip G. Freelon, the lead architect of the Smithsonian’s National Museum of African-American History and Culture in Washington.

In addition to rehabilitating the community center and pool house, Mr. Freelon designed a striking new recreation center featuring a well-equipped gym and competition-size basketball court. Elsewhere in the park, he built a baseball diamond, a tennis court, a playground, a picnic area and an outdoor stage for live concerts. Mr. Freelon has clearly taken cues from Bryant Park in New York and Millennium Park in Chicago on how to maximize every square foot of green space. And with a zero-impact geothermal heating and cooling system, the park is on track for LEED Platinum certification.

Initially, there was some skepticism in Third Ward about the renovation, especially given the influx of wealthier, often white residents who have been filling up new townhouse developments over the past few years, attracted by the relatively cheap home prices and proximity to downtown.

“You had a lot of folks saying, ‘The park isn’t for us; white folks are going to come in and take it over,’” Mr. Manning said. “But now that the park is open and folks are using the pool and the rec center, some of that is calming down. I always tell folks, look, take ownership. This is a park for everybody, no matter what your race is.” (On two recent visits to the park, the overwhelming majority of park users were black.)

There were also concerns about the park’s $34 million budget, which was raised from private foundations, individual donors and a local economic development zone. “People say we have streets that need to be paved,” said the development zone’s vice chairwoman, Algenita Scott Davis. “Well, they will continue to be paved. But in the meantime, we’re going to celebrate who we are. I’m sure the park’s founders were attacked left and right by people saying they were wasting money on a park.”

The Houston mayor, Sylvester Turner, who is black and supported the renovation, said the city was working on ways to lighten the tax burden for longtime Third Ward residents so they can stay in their homes. But he made no apologies for trying to improve the neighborhood’s quality of life: “The people of Third Ward deserve a park with all of the amenities, that is second to no other park in the city. African-Americans deserve that.”

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Even before the park reopened, a number of businesses catering to the neighborhood’s newest residents had appeared. Across the street from the park, below the old Eldorado Ballroom, are the Crumbville, TX bakery, which sells vegan cookies and brownies, and the NuWaters food co-op. A few blocks down Emancipation Avenue, Doshi House serves sustainably sourced coffee and vegetarian meals. (Emancipation Avenue used to be called Downing Street, after a local Confederate officer; the Houston City Council voted in January to change the name.)

The latest business to open on the park periphery is the Rustic Oak Seafood Boiler Shack, which serves coastal Cajun cuisine. The owner and chef, Wendell Price, grew up on MacGregor Way, a more affluent part of Third Ward, and remembers the area around Emancipation Park as a food desert. “When I came down to hang in this area, you literally couldn’t get a salad,” he said.

Mr. Price, who previously operated a restaurant in Houston’s trendy Montrose neighborhood, said he would never have considered setting up shop in Third Ward if not for the Emancipation Park renovation. “I’ve been watching this spot for about six years, hoping that something would happen to the park, because if it didn’t, I wouldn’t be doing this. There’d be no way,” Mr. Price said.

Not everything has gone smoothly. His restaurant has been robbed four times in the past month; on one of those occasions, the thieves made off with his air-conditioning unit. Mr. Price said he carries a gun after dark. For him, gentrification cannot come soon enough. “It’s a slow progression, getting the bad out and the good in,” he said.

And although he loves being across from the new park, there is one thing he is not crazy about. “Do I like the name Emancipation Park?” he said. “I don’t, it’s too dated. I call it E.P.”