Representatives Bob Latta of Ohio, John Shimkus of Illinois and Joe Wilson of South Carolina were accompanied by Cal Dallas, Alberta's minister of intergovernmental affairs.
Dallas says the sights shown to the U.S. politicians presented an unbiased view of the region.
He says they were told about the industry's efforts in development and reclamation.
All three congressmen have been vocal supporters of TransCanada's Keystone XL pipeline, which would take oil from northern Alberta to Texas.
They have said the project has the potential to create jobs while providing much-needed oil to American consumers.
The trio were taken on a tour of facilities owned by Shell and Nexen as well as a reclamation project by Syncrude.
Their visit came the same day that actor Robert Redford called the pipeline a massive environmental threat.
Redford posted a video on the New York Times website urging the Obama administration to block the $7 billion project, which he said would carry "the dirtiest oil on the planet" through the American heartland.
TransCanada spokesman Terry Cunha said the actor is entitled to his opinion.
(CHED, The Associated Press)
