Excerpts from Wikipedia and more

Zilker is a neighborhood that extends south of Lady Bird Lake, approximately bounded by the Union Pacific Railway to the southeast/south (Lamar Boulevard south of Oltorf), Barton Skyway to the south, Rabb Road and Robert E Lee Road to the west and Lady Bird Lake to the north. Directly northwest of Zilker is Barton Hills Neighborhood, which connects back to Zilker Park via the Barton Creek Greenbelt.

Zilker Neighborhood Association map

In 1918, Andrew Jackson Zilker deeded 35 acres surrounding Barton Springs to the City of Austin. Most of the first homes in the Zilker area were constructed in the late 1920s.

Much of the west end of Zilker was owned by Vincent Canizzo until the late 1940s when the City of Austin, using eminent domain, forced him to sell the land on which Zilker Elementary currently sits. Shortly thereafter, the remaining land — from Ann Arbor Road to Rabb Road — was split into the Canizzo Subdivision.

The Umlauf Sculpture Garden, Shady Grove Restaurant, Green Mesquite Restaurant, the original Chuey’s Restaurant, Peter Pan Mini Golf, Uchi Restaurant, the flagship theater of Alamo Drafthouse, Saxon Pub, South Austin Museum of Popular Culture, Planet K, Horseshoe Lounge, Austin’s Pizza, Paggi House, La Ferria Restaurant, Matt’s El Rancho, Maria’s Tacos, the original Schlotzsky’s, Bicycle Sport Shop, Butler Shores Pitch and Putt, and the Pfluger Pedestrian Bridge are popular locations for residents of South Austin.

Zilker Park is best known for Barton Springs; the Zilker Christmas Tree and Trail of Lights; and music festivals such as Austin City Limits.