[12] Seeking to expand its presence in the United States, in 2016, TransCanada acquired Columbia Pipeline Group (CPG) for US$13 billion from NiSource's Shareholders.

The CPG acquisition added a pipeline network in Pennsylvania and surrounding states, where the Marcellus and Utica shale gas formations are located.

[22][23][24][25] The investment and construction decisions for the LNG Canada and Coastal GasLink Pipeline Project were officially confirmed early October 2018, for completion by 2024–2025.

However, hereditary chiefs of the Wetʼsuwetʼen have denied consent to construct the pipeline on the company's preferred route through culturally and ecologically sensitive lands in their unceded territory, leading to nationwide protests.

In October 2012, TransCanada formed a 50–50 CAD$3bn joint-venture with Phoenix Energy Holdings Ltd. (the Canadian subsidiary of PetroChina) to develop the 500 km Grand Rapids Pipeline.

[32] The 4,324 km-Keystone Pipeline System transports crude oil from Hardisty, Alberta, to U.S. markets at Wood River and Patoka, Illinois, Cushing, Oklahoma, and the U.S. Gulf Coast.

[34] The proposal faced widespread grassroots opposition with tactics including tree sits in the path of the pipeline[35] and civil disobedience by celebrities.

state that by developing the oil sands, fossil fuels will be readily available and the trend toward warming of the atmosphere won't be curbed.

[citation needed] In October 2011, TransCanada was involved in up to 56 separate eminent domain actions against landowners in Texas and South Dakota who refused to give permission to the company to build the Keystone Pipeline through their land.

[41][42] Early in his tenure in 2017, President Donald Trump signed presidential memoranda to revive both Keystone XL and Dakota Access pipelines.

[47] According to The New York Times, despite the coronavirus pandemic, a down turn in the global economy, and "plunging oil prices", Premier Kenney said that Alberta could not afford "for Keystone XL to be delayed.

[50][48] The premier also said that over the next twenty years, the financial benefits to Alberta through tax and royalty revenue would be approximately CA$30 billion.

[50] In response to Alberta's financial support, in March, TC Energy "approved construction of the US$8-billion project to transport up to 830,000 barrels per day of oil.

"[51] According to a Canadian Press March 31, 2020 article Premier Kenney estimated that "1,400 direct and 5,400 indirect jobs" would be created in Alberta during construction.

[49] In April, shortly after construction on Keystone XL began, Judge Brian M. Morris of the Federal District Court in Montana suspended the United States Army Corps of Engineers (USACE)'s program allowing permits for pipelines to cross waterways, in spite of the Clean Water Act (CWA).

In July 2020, the Supreme Court of the United States declined to block Judge Morris' ruling, effectively halting all construction on the XL Pipeline.

[54] TransCanada reported it discovered the leak in Amherst, South Dakota, at 6 am on Thursday after systems detected a drop in pressure in the northern leg of the pipeline.

[57] Also in April 2018, Reuters reviewed documents that showed that Keystone had "leaked substantially more oil, and more often, in the United States than the company indicated to regulators in risk assessments before operations began in 2010".

The legislation, which Governor Kristi Noem signed into law in March 2019, created a fund to cover the costs of policing pipeline protests, and was accompanied by another law which sought to raise revenue for the fund by creating civil penalties for advising, directing, or encouraging persons participating in rioting.