Southlake will throw its biggest birthday party in decades on Saturday, Sept. 12, when the city marks 70 years since incorporation with a free evening celebration at Town Square.

Celebrate Southlake runs from 4 p.m. to 9 p.m. and features live music, food trucks, family activities, free tree saplings and a light show finale, according to the city's official announcement posted July 29.

No tickets or registration are required.

Two bands are scheduled: New Mix Vibez and The Boogies, with the anniversary light show closing the night at 9 p.m., according to a band lineup posted by Visit Southlake on Friday, Aug. 14.

A city born to block annexation

Southlake incorporated in 1956 after rumors spread that the city of Hurst planned to annex land stretching to Lake Grapevine. Residents launched a petition drive, and the incorporation vote passed 30-24, according to the Southlake Historical Society. The city's first mayor, A. Gail Eubanks, took office, and his daughter Suzanne suggested the name Southlake for the community's location south of the lake.

"I don't think that there's any of us that lived here that were very excited about being Southlake. I wasn't. We just didn't want to be Hurst. But they were coming right down the road after us," longtime resident Mabel Cate recalled in an oral history preserved by the Historical Society.

Colleyville and Westlake also incorporated that same year. The Town of Westlake nodded to the shared history in a comment on the city's Facebook post: "From one 70-year-old to another, HAPPY BIRTHDAY, NEIGHBOR!"

What started as roughly 200 residents within 1.62 square miles has grown to more than 32,000 people by the 2020 Census, fueled by the opening of DFW International Airport in 1974. Town Square's first phase opened in 1999, with its second and third phases following in 2006.

Free trees, lasting roots

The Sept. 12 celebration doubles as a distribution point for the city's signature anniversary project: planting 2,026 trees across Southlake in 2026. Free saplings will be available for residents who want to plant at home. Spring sapling purchases through the program have closed, with fall opportunities expected.

Sponsorship tiers for the tree initiative range from $500 for a single park tree up to $20,000 for a "Legacy Canopy" package supporting 200 five-gallon trees or 40 large park trees.

The Sept. 12 event is part of a year-long series of 70th anniversary milestones the city has been running since early 2026, including spotlights on Feedstore BBQ & More's 25th anniversary, the Hilton Southlake, White's Chapel Methodist Church's 150th year and a Liberty Tree Dedication.

Celebrate Southlake is free and open to the public. The city has not announced parking details or an expected attendance figure.