"The northern leg of Keystone XL, which runs from Alberta’s tar sands south to Steele City, Nebraska, is under additional review by the State Department. The Department will likely complete its analysis by early 2013. Transcanada, the company behind the pipeline, agreed to reroute the northern section after major concerns were raised about the impacts it could have on Nebraska’s Ogallala Aquifer.
But construction has already begun on the southern leg of the pipeline, which runs from Cushing, Oklahoma to various refineries in southern Texas. Construction on the 'Gulf Coast segment' of the pipeline began in early August after President Obama directed his administration to 'make this project a priority' in March. (A third, middle portion running from Steele City to Cushing is already online)."