Enbridge, Inc. is a Canadian multinational energy transportation company based in Calgary, Alberta. It focuses on the transportation, distribution and generation of energy, primarily in North America. As a transporter of energy, Enbridge operates in Canada and the United States, the longest crude oil and liquid hydrocarbons transportation system in North America. As a distributor of various fuels, it owns and operates Canada's largest natural gas distribution network, providing distribution services in Ontario, Quebec, New Brunswick and New York State.

The company was initially incorporated by Imperial Oil as Interprovincial Pipe Line Ltd. (IPL) on April 30, 1949 shortly after Canada's first major oil discovery at Leduc, Alberta. At the same year the company built its first oil pipeline from Leduc to Regina, Saskatchewan. In 1950, it was expanded through Gretna, Manitoba, to Superior, Wisconsin, in the United States. To operate the United States portion of the pipeline, the Lakehead Pipe Line Company (now: Enbridge Energy Partners) was created. In 1953 the pipeline was expanded to Sarnia, Ontario and in 1956 to Toronto and Buffalo, New York.

In 1953, IPL was listed on the Toronto and Montreal exchanges.

In 1983 IPL built Norman Wells pipeline and joined Frontier Pipeline Company. In 1986, through a series of stakes' exchanges IPL gained control of Home Oil and in 1988 it changed its name to Interhome Energy Inc. In 1991, it changed its name to Interprovincial Pipe Line Inc. in 1991. In 1992 Interprovincial Pipe Line Inc. was acquired by Interprovincial Pipe Line System Inc. which changed its name to IPL Energy Inc in 1994, after acquisition of Consumers' Gas (now Enbridge Gas Distribution Inc.) and diversification into the gas distribution business. In addition it acquired stakes in AltaGas Services and the electric utility of Cornwall, Ontario. Through 1990s the company expanded its gas pipeline network and acquired stake in the Chicap oil pipeline. It also built the Athabasca Pipeline from northeastern Alberta to the main pipeline system. In 1995 the company also expanded its activities outside of North America by taking a stake in the Ocensa pipeline. This stake was sold in 2009. IPL Energy became Enbridge Inc in 1998. The Enbridge name is a portmanteau from "energy" and "bridge".

In 2000s Enbridge introduced several large projects. In 2006 it announced the Enbridge Northern Gateway Pipelines Project from Athabasca to Kitimat, British Columbia. Same year it announced the Alberta Clipper pipeline project from Hardisty, Alberta to Superior, Wisconsin, to connect oil sands production area with the existing network. This pipeline became operational in 2010.

In 2009, Enbridge bought the Sarnia Photovoltaic Power Plant and expanded it up to 80 MW, which was the world's largest photovoltaic power station at that time.

In January 2017, Enbridge said it would acquire Midcoast Energy Partners for $170 million in cash. After the Chippewas of the Thames community filed suit against Enbridge to stop its controversial "Line 9" pipeline, in July 2017, the Supreme Court of Canada ordered the community to pay Enbridge’s legal costs.

Enbridge transports crude oil, liquids and natural gas in pipelines that total approximately 46,670 kilometres (29,000 mi) in Canada and the United States.

The company is the largest transporter of crude oil in Canada with 2.2 million barrels per day (350×10^ m/d) of oil and liquids. The Enbridge Pipeline System is the world's longest crude oil and liquids pipeline system, located in both Canada and the United States.

Enbridge has several new capacities and expansion projects, including construction of Northern Gateway, expansion of Alberta Clipper, renovation of Line 6, reversal of Line 9 and others. Its Light Oil Market Access initiative is a project light crude oil from North Dakota and Western Canada to refineries in Ontario, Quebec, and the U.S. Midwest. Eastern Access, including a reversal of Line 9, is a project to deliver oil Western Canada and Bakken to refineries in Eastern Canada and the midwest and eastern U.S. Western Gulf Coast Access, including reversal and expansion of the Seaway Pipeline and the Flanagan South Pipeline, is a plan to connect Canadian heavy oil supply to refineries along the Gulf Coast of the United States.

Enbridge also gathers, processes, and transports natural gas. It has interest in the 2,986 kilometres (1,855 mi) Alliance Pipeline and the 560 kilometres (350 mi) Vector Pipeline. Through its subsidiaries Enbridge Gas Distribution and Union Gas it is Canada's largest natural gas distribution utility.

Enbridge has entered the power transmission business to facilitate the import and export of power, allowing markets to have efficient and economic access to existing and new-generation sources.

Enbridge's Montana-Alberta Tie-Line (MATL) is a 300-megawatt (MW), 230-kilovolt (kV) electrical transmission line allowing movement of power between Alberta and Montana. The MATL project, which was placed in service the fall of 2013, supports ongoing development of a rich wind-powered generation resource and allows electrical energy to flow in both directions. The transmission line is 210 miles (345 km) long and runs between the Lethbridge, Alberta area and the Great Falls, Montana area. Roughly 1/3 of the line is in Canada and 2/3 in the U.S.

Enbridge rail facilities are responding to producer and shipper demands for more flexible, economical transportation of high-quality crude oil from the Bakken Formation, located in eastern Montana, western North Dakota, and southern Saskatchewan and Manitoba.

Using data from Enbridge's own reports, the Polaris Institute calculated that 804 spills occurred on Enbridge pipelines between 1999 and 2010. These spills released approximately 161,475 barrels (25,672.5 m) of crude oil into the environment.

On July 4, 2002, an Enbridge pipeline ruptured in a marsh near the town of Cohasset, Minnesota, in Itasca County, spilling 6,000 barrels (950 m) of crude oil. In an attempt to keep the oil from contaminating the Mississippi River, the Minnesota Department of Natural Resources set a controlled burn that lasted for one day and created a smoke plume about 1-mile (1.6 km) high and 5 miles (8.0 km) long.

In 2006 there were 67 reportable spills totaling 5,663 barrels (900.3 m) on Enbridge's energy and transportation and distribution system; in 2007 there were 65 reportable spills totaling 13,777 barrels (2,190.4 m)

On March 18, 2006, approximately 613 barrels (97.5 m) of crude oil were released when a pump failed at Enbridge's Willmar terminal in Saskatchewan. According to Enbridge, roughly half the oil was recovered.

On November 28, 2007, two workers were killed when an uncontrollable blaze started at an Enbridge terminal/tank farm in Clearbrook, Minnesota. The fire forced Enbridge to shut down the operating pipelines in the area, temporarily halting roughly 1/5 of US imports and increasing the price by nearly $1 per barrel. The pipe had leaked two weeks before and a temporary repair had been put in place. As workers were removing the temporary repair, oil began leaking and the fumes ignited. As of 2013, local municipal water supplies in Clearbrook would be insufficient to put out another fire should one occur.

On January 1, 2007, an Enbridge pipeline that runs from Superior, Wisconsin to near Whitewater, Wisconsin cracked open and spilled ~50,000 US gallons (190 m) of crude oil onto farmland and into a drainage ditch. The same pipeline was struck by construction crews on February 2, 2007, in Rusk County, Wisconsin, spilling ~201,000 US gallons (760 m) of crude, of which about 87,000 gallons were recovered. Some of the oil filled a hole more than 20 feet (6.1 m) deep and contaminated the local water table.

In April 2007, roughly 6,227 barrels (990.0 m) of crude oil spilled into a field downstream of an Enbridge pumping station near Glenavon, Saskatchewan.

In 2009, Enbridge Energy Partners, a U.S. affiliate of Enbridge Inc., agreed to pay $1.1 million to settle a lawsuit brought against the company by the state of Wisconsin for 545 environmental violations. In a news release from Wisconsin's Department of Justice, Attorney General J. B. Van Hollen said "...the incidents of violation were numerous and widespread, and resulted in impacts to the streams and wetlands throughout the various watersheds". The violations were incurred while building portions of the company's Southern Access pipeline, a project to transport crude from the oil sands region in Alberta to Chicago.

In January 2009, an Enbridge pipeline leaked about 4,000 barrels (640 m) of oil southeast of Fort McMurray at the company's Cheecham Terminal tank farm. Most of the spilled oil was contained within berms but about 1% of the oil, about 40 barrels (6.4 m), sprayed into the air and coated nearby snow and trees.

On January 2, 2010, Enbridge's Line 2 ruptured near Neche, North Dakota, releasing about 3,784 barrels of crude oil, of which 2,237 barrels were recovered.

In April 2010, an Enbridge pipeline ruptured spilling more than 9.5 barrels (1.51 m) of oil in Virden, Manitoba. This oil leaked into the Boghill Creek, which eventually connects to the Assiniboine River.

In the July 2010 Kalamazoo River oil spill, a leaking pipeline spilled more than 1,000,000 US gallons (3,800 m) of oil sands crude oil into Talmadge Creek leading to the Kalamazoo River in southwest Michigan on July 26, near Marshall, Michigan. A United States Environmental Protection Agency update of the Kalamazoo River spill concluded the pipeline rupture "caused the largest inland oil spill in Midwest history" and reported the cost of the cleanup at $36.7 million (US) as of November 14, 2011. The cleanup is unfinished as of March 2013. PHMSA raised concerns in a Corrective Action Order (CAO) about numerous anomalies that had been detected on this pipeline by internal line inspection tools, yet Enbridge had failed to check a number of those anomalies in the field. The Michigan spill affected more than 31 miles (50 km) of waterways and wetlands and about 320 people reported symptoms from crude oil exposure. The National Transportation Safety Board said at $800 million, it was the costliest onshore spill cleanup in U.S. history. The NTSB found Enbridge knew of a defect in the pipeline five years before it burst. In June 2013, a Kalamazoo man lodged himself into an Enbridge pipeline in Marshall, MI to protest Enbridge's lack of accountability for the 2010 spill and to encourage landowners along Enbridge's Line 6B expansion to offer increased resistance to construction in 2013.

On September 9, 2010, a rupture on Enbridge's Line 6A pipeline near Romeoville, Illinois, released an estimate 7,500 barrels (1,190 m) of oil into the surrounding area.

Enbridge Pipelines (Athabasca) Inc., or Athabasca pipelines, subsidiary of Enbridge Inc., (TSX:ENB) (NYSE:ENB) reported a pipeline leak site, about 70 kilometres southeast of Fort McMurray, on June 22, 2013 of approximately 750 barrels of light synthetic crude oil from Line 37 near Enbridge’s Cheecham, Alberta, terminal. Line 37, constructed in 2006, a 17-kilometre-long, 12-inch diameter pipe links the Long Lake oilsands upgrader to the Cheetham terminal and is part of Enbridge’s Athabasca system. Unusually heavy rainfall in the region, that caused the 2013 Alberta floods, may have caused "ground movement on the right-of way that may have impacted the pipeline." Enbridge’s Athabasca (Line 19) shares a portion of right of way with Line 37 and Enbridge's Wood Buffalo/Waupisoo (Line 75/18) which also shares a portion of right of way with Line 37, a major part of the network that serves Alberta's oilsands, were closed down as a precautionary measure. Operations between Hardisty and Cheecham were restored on June 23 when Enbridge’s Athabasca pipeline (Line 19) was restarted.

On July 1, 2013, WWMT in Michigan reported that the Michigan Department of Environmental Quality had issued a citation against Enbridge for contamination of North Ore Creek by an Enbridge pipeline maintenance activity.

On January 30, 2017, a road crew punctured the Seaway S-1 crude oil pipeline in Texas, which is jointly joined by Enterprise Products Partners and Enbridge Inc. through the joint venture Seaway Crude Pipeline Company. Two days later, it was unclear how much oil had spilled over the nearby Highway 121 northeast of Dallas. After the incident, supply concerns reportedly helped push "oil prices 2% higher in early trading to nearly $54 a barrel.

In May 2012, West Coast First Nations members and supporters protested near Enbridge's Annual Shareholder's meeting, against the proposed Northern Gateway Project.

On May 31, 2012, the Vancouver Observer reported about 40 protesters outside the Canadian Oil and Gas Export Summit, protesting the proposed Enbridge Northern Gateway Project.

On July 17, 2012, a group calling itself "We are the Kalamazoo" protested against Enbridge's response to the Kalamazoo spill and its plans to construct the line 6B pipeline. This protest was on the second anniversary of the Kalamazoo spill.

On September 14, 2012, WLNS-TV reported clashes between Enbridge and landowners over eminent domain.

On November 12, 2012, the Lansing State Journal reported that the head of the Line 6B pipeline project stated that he had never seen as much organized landowner resistance before despite 30 years in the pipeline industry. They noted that this was probably because of the 2010 Kalamazoo River spill.

On April 20, 2013, a group of about 30 protesters gathered at the site of the Kalamazoo River oil spill to protest against tar sands oil, fracking, and Enbridge's response to the spill. Kalamazoo County Commissioner Jeff Heppler, whose property was affected by the spill, was present at the protest and stated, "'All I am asking is Enbridge do what they said they said they will do and what is right and take care of everybody, including the businesses that were adversely impacted by the oil spill.'"

In May 2013, Hamilton area residents protested the reversal of flow in Line 9 and temporarily closed Ontario Highway 6.

On June 6, 2013, a group called Hamilton 350 sent a letter of complaint to the Hamilton (Ontario) police service (HPS) for accepting over $44,000 in donations from Enbridge. The letter questions whether police officers would be impartial during any anti-Enbridge protests, given the donation. The letter questions, "If there were a standoff between, on the one side, environmentalists and/or native people (who claim the spot at which the Grand River is crossed by this pipeline) and, on the other side, Enbridge, Inc., would officers of the HPS be able to be truly impartial?"

One June 26, 2013, Hamilton Police arrested at least 10 people who occupied an Enbridge compound for six days to protest the expansion of Enbridge's Line 9 and intent to ship diluted bitumen through the line.

On July 22, 2013, a group of protesters locked themselves to equipment at an Enbridge pipeline construction site in Stockbridge, Michigan. Protesters stated that they had to take matters into their own hands given that state regulators were failing the public, "We felt that there was no other option."

Throughout Minnesota in 2013, activists from the Red Lake and Leech Lake reservations, members of the Indigenous Environmental Network, Sierra Club, Honor the Earth, and MN350 have been taking action against the Enbridge Alberta Clipper pipeline which runs through the North half of Minnesota. At the Red Lake reservation, the only reservation in the nation to have a pipeline illegally operating under its soil without easements, a permanent encampment has been erected over the pipeline Right-of-Way, causing Enbridge to be fined for every day the pipeline is in operation. Activists from these organizations have organized demonstrations and disrupted hearings with the Minnesota Public Utilities Commission to demand that permission to increase the flow of dilbit through the Alberta Clipper pipeline be denied. In August 2013, the PUC agreed that a contested-case hearing take place to order further assessment of the environmental impacts of the increased capacity.

A September 16, 2013, "Inside Climate News" report by Pulitzer Prize–winning journalist David Hasemeyer describes how many Michigan landowners are concerned about the safety of new Enbridge pipeline being laid within a few feet of their homes, and the lack of regulations for how close a pipeline can be constructed to an existing home. The article quotes Richard Kuprewicz, president of an engineering consulting company and an adviser to Pipeline Hazardous Materials Administration: "Clearly the pipeline safety regulations aren't adequate in this area and the siting regulations aren't adequate," Kuprewicz said. "It's a bad combination." Homeowners are questioning Enbridge's claims of putting safety first while also placing pipelines sometimes within less than 10 feet of homes.

On September 3, 2016, security personnel from the Dakota Access Pipeline company attacked a group of Native American protesters with dogs and pepper spray but were eventually driven off by protesters. The group was protesting the construction of a crude oil pipeline. Enbridge has announced plans to acquire a portion of the Dakota Access pipeline in a $2 billion deal.