Zilker Park, Urban park in south Austin, Texas, United States

Zilker Metropolitan Park covers over 350 acres at the junction of Barton Creek and the Colorado River in south Austin. Its centerpiece is a large, flat, closely mowed lawn that opens toward a line of trees and the city skyline; a low, curved white backstop sits near the center-left. The park also holds Barton Springs Pool, the Zilker Botanical Garden, the Austin Nature & Science Center, and the Umlauf Sculpture Garden.

The land around Barton Springs was claimed by William Barton in the 1830s for a cattle ranch, and the Rabb family ran mills on Barton Creek there in the 1860s. Andrew Jackson Zilker bought the 350-acre plot between the Colorado River and Barton Creek, used the spring water in his ice-making business, then sold it to Austin in 1917, 1923 and 1931, giving the proceeds to a trust for the city's public schools. In the 1930s the city turned the ranch into a park with help from the Civil Works Administration, and in 1934 it was named Zilker Metropolitan Park.

The park's name comes from Andrew Jackson Zilker, whose 1917 land sale funded an Austin public schools trust. Each May, local companies stage free Shakespeare in the Park at the Zilker Hillside Theater, which also hosts an annual summer musical. The Zilker Botanical Garden holds its Gardens Festival every spring, and a kite festival fills the lawns yearly.

Zilker Park sits at the junction of Barton Creek and the Colorado River in south Austin, with the Roy and Ann Butler Trail looping Lady Bird Lake beside it and the Violet Crown Trail running south from Barton Springs Pool. The grounds are open daily; the miniature railway, Barton Springs Pool and the botanical garden keep their own hours.

The Zilker Zephyr miniature railway, a 12 in (305 mm) gauge line, opened in 1961 and carried passengers on a tour around the park until erosion closed it in 2019; it reopened in August 2023 as the Zilker Eagle.