Hundreds of Canadian residents, including a former Conservative MP and an aide to a Liberal cabinet minister, have been contributing money to the U.S. election campaign, CBC News has learned.

The vast majority of the contributions from Canada went to Democratic presidential candidates Hillary Clinton and Bernie Sanders or to the Democratic Party. Of the more than 450 individual contributors identified by CBC News, only two contributed to Republican presidential candidate Donald Trump.

Money from a small number of Canadian residents found its way to Republican candidates – usually through corporate political action committees or PACs set up by American companies with offices in Canada like Resolute Forest Products, the Ford Motor Company and Chevron

While many of the contributors are Americans or dual citizens living in Canada, others appear to be Canadian citizens. The Federal Election Commission's database shows candidates, particularly former Democratic presidential contender Bernie Sanders, have refunded more than $200,000 in contributions to donors living in Canada as they hadn't proved they were Americans.

In February, the U.S. Federal Election Commission (FEC) warned the Sanders campaign it risked violating U.S. election laws by accepting contributions from non-Americans.

Canadian citizens can't give

Under U.S. election law, it is illegal for someone who is not an American citizen to contribute to a U.S. election campaign. If a campaign cannot prove the contributor is an American, it has 10 days to refund the money, said Julia Queen, spokeswoman for the FEC.

There is no rule preventing Canadians from volunteering their time to help a U.S. candidate.

Attempts to reach spokespeople for the Clinton, Trump or Sanders campaigns have been unsuccessful.

The home provinces where most of the donors live are Ontario and British Columbia. While many donors, particularly to Sanders' campaign, listed their occupation as not employed, professors and teachers were among the occupations most often cited.

Former Democratic presidential hopeful Bernie Sanders was one of the biggest recipients of donations from Canadian residents - many of which were refunded. (Matt Rourke/Associated Press)

CBC News also found two companies based in Canada listed in the FEC database as making contributions to Super PACs, organizations that raise money for candidates but are not bound by the same rules as political parties.

However, one of those companies, Vancouver-based Templates for Business, says it ended up in the database in error, when a $10,000 contribution to the National Association of Realtors to support "issues advocacy" went instead to the NAR's Congressional Fund Super PAC. The NAR said the money was refunded after it realized it came from outside the country.

Templates for Business Managing Partner Paul Pimstone said the money was intended to be used for the NAR's lobbying efforts in the U.S., where he does an important part of his business, and was not connected to the U.S. election. He said the money was redirected to the proper fund.

"We donated to the NAR Corporate Ally Program as a show of support to our U.S. MLS customer and towards initiatives which can help the Real Estate MLS (Multiple Listing Service) industry protect its data."

Questions about foreign money

As one of the hardest fought elections in U.S history comes down to the wire, questions have been swirling about presidential campaigns being willing to accept money from outside the U.S.

Contributions to U.S. parties or Political Action Committees by Canadian residents, according to CBC News analysis of U.S. Federal Election Commission data. (CBC)

Emails recently made public by Wikileaks reveal that Clinton's campaign was willing to accept foreign donations after the Clinton Foundation stopped accepting money from foreign governments. Donald Trump has seized on the revelations, calling for a ban on foreign lobbyists donating to U.S. candidates.

However, there have also been reports of Trump's campaign accepting money from people living outside the U.S.

An investigation by the British newspaper The Telegraph revealed in October that fundraisers with the pro-Trump Super PAC, Great America PAC, were willing to accept money from foreign backers and promised influence in return, if Trump became president.

Long and costly campaign

The contributions from Canadian residents identified by CBC News ranged from $1 donations to Bernie Sanders's campaign to the $25,000 Toronto's SRI Capital donated to the pro Jeb Bush super PAC Right to Rise USA. These are only a small part of the billions of dollars being raised – and spent – by candidates across the U.S.

However, it is difficult to know exactly how much money is coming from Canadian residents, most of whom would be dual or American citizens, or exactly how many people have contributed.

The FEC contributions database does not classify contributions according to the country of origin. While there is a category for "foreign country," many of the donations from Canada to campaigns like Clinton's and various PACs, do not list that code in FEC filings.

Consequently, identifying contributions from Canadian residents can be a time consuming and meticulous exercise.

There is also a lag time between the time a donation is made and the time it is listed in the FEC database, which means more recent contributions – and refunds – from Canadian residents would not yet appear.

Despite the limitations when it comes to determining the full extent of the financial contributions by Canadian residents, it is clear that Tuesday's election has garnered a lot of interest north of the border, including among some who are usually more involved in Canadian politics.

Conservative MP gives

FEC records show that Bob Dechert, former Conservative MP for Mississauga-Erindale, who recently announced plans to seek an Ontario PC nomination, donated $250 on July 26 to the Oklahoma Leadership Council, which contributes money to Republican candidates. Dechert's contribution was refunded on Aug. 10.

Reached by CBC News Tuesday, Dechert said he had no idea the registration fee he paid to attend the Republican Party Convention in Cleveland as a guest of the Oklahoma Republican Party Committee would be recorded in the FEC database as a contribution. He later received a refund in the mail from the Oklahoma Republican Committee.

"We didn't donate, there was no contribution, there was no campaign," said Dechert who is not an American citizen. "It was just to sit in the observer section of the convention."

'I've never seen people so hysterical' - Ben Gelfand , Trump supporter

Jordan Owens, who now works as press secretary to Defence Minister Harjit Sajjan, made two contributions totaling $205 in June 2015 to Clinton's Hillary for America campaign. At the time, she worked for the Gandalf Group.

"I have always supported the Democratic Party," said Owens, who has American citizenship.

Toronto's Ben Gelfand was one of only two Canadian residents identified by CBC News who contributed to Donald Trump's campaign. Gelfand, who works with Trapeze Asset Management, donated $1,000 to Trump's campaign on June 23.

Gelfand, a U.S. citizen, thinks "it's good to have a little skin in the game" and he likes what he hears from Trump.

Former Conservative MP Bob Dechert contributed $250 to the Oklahoma Leadership Council which donates money to Republican candidates. (House of Commons)

"I think that particular candidate I am supporting is using his own money and only small donations from individuals as opposed to the other candidate which is largely funded by other sovereign countries and S&P 500 companies," said Gelfand, who has already cast his vote in the battleground state of Ohio.

"So I wanted to help out."

Gelfand said there are far more Trump voters than people realize but they have been "shamed into silence."

"People are almost hysterical over this election. I've never seen people so hysterical," he said, speculating it could have something to do with the economy being "so, so bad."

Jay Baltz, a senior scientist at the Ottawa Hospital Research Institute and professor at the University of Ottawa, donated $500 to Hillary for America, saying "in no way is Donald Trump safe or qualified to be president of the U.S."

A region breakdown of contributions from Canadian residents to U.S. parties or Political Action Committees, according to CBC News analysis of U.S. Federal Election Commission data. (CBC)

'Astounded' by election

"In this particular election it is especially clear that the Republican nominee is a lunatic," said Baltz, a dual citizen.

"He's embracing overt racists and white nationalists and refusing to distance himself from people like (former Ku Klux Klan leader) David Duke until the very last second when he is pushed on air."

In this particular election it is especially clear that the Republican nominee is a lunatic - Jay Baltz, Clinton supporter

London, Ont.'s George Crowell, monetary policy chairman for the Council of Canadians and a dual citizen, donated $300 to Bernie Sanders because of his policies, but ended up voting for Clinton.

"The choice was not a happy one for me but Trump is so scary," said Crowell, who voted in Illinois where he last lived in 1968.

Erik Mont, a doctor with Nova Scotia's Medical Examiners Service and an American, donated to the Sanders campaign because "his platform spoke to me." He was unaware the Sanders campaign had refunded his money – possibly because he didn't feel comfortable supplying some of the information it requested over the web.

Mont is "astounded" at how the election has evolved. "As an American living in Canada, it is embarrassing."

CBC Poll Analyst Eric Grenier looks at the polls in Iowa, Wisconsin and Michigan. 4:36

Elizabeth Thompson can be reached at elizabeth.thompson@cbc.ca