|Neighborhood of Pittsburgh|
Along Pioneer Avenue in Brookline
|• Total||2.082 sq mi (5.39 km2)|
|• Density||6,300/sq mi (2,500/km2)|
Brookline was a part of the larger West Liberty Borough before its absorption into Pittsburgh in 1908. Early in its history, the area was mostly inhabited by miners and farmers. At the turn of the century, when the mining industry in the area declined, only farms were left.
Dawn of the 20th century
The dawn of the 20th century brought many technological advances that helped the South Hills of Pittsburgh flourish. First, the transportation of coal from the area opened up the Pittsburgh & Castle Shannon Railroad Co. to install lines going to the area. This included a tunnel to be bored from downtown Pittsburgh, through Mt. Washington, and to exit right above South Hills Junction. With the age of automobiles looming, a few decades later the Liberty Tunnel was completed. This helped create a boom in the South Hills areas.  
Brookline was linked by streetcar to downtown Pittsburgh in 1905 by Pittsburgh Railways who built a single line south along West Liberty Avenue, turning east on a private right of way and then following Brookline Boulevard to Saw Mill Run. This initial line was cut back to Edgebrook Avenue a year later, but in 1909 the track was doubled and a loop put in near the end of Witt Street. In 1915 the line was extended south along West Liberty Avenue to Dormont where it linked with the 42 Dormont line. The 39 Brookline service closed in 1966.
- "PGHSNAP 2010 Raw Census Data by Neighborhood". Pittsburgh Department of City Planning PGHSNAP Utility. 2012. Retrieved 21 June 2013.
- "The History of Brookline - The first 250 Years".
- "Liberty Tunnels - Bridges and Tunnels of Allegheny County and Pittsburgh, PA".
- "The Liberty Tunnels and the Liberty Bridge".
- "The Brookline Connection - Trolley Service in Brookline". October 6, 2009. Retrieved October 9, 2009.
- "Pittsburgh Railways Online - A Trolley Car Tragedy". February 18, 2002. Retrieved August 14, 2009.
- Toker, Franklin (1994) . Pittsburgh: An Urban Portrait. Pittsburgh: University of Pittsburgh Press. ISBN 0-8229-5434-6.