Hillary Clinton's healthy lead over Donald Trump among younger voters has been disintegrating, with some younger voters switching over to libertarian Gary Johnson in critical swing states.

To counter the drop-off, the Clinton camp is sending its top surrogates to college campuses around the country. First Lady Michelle Obama campaigns for Clinton at George Mason University in Fairfax, Virginia today.

First lady Michelle Obama campaigned at the George Mason University college campus in Virginia on Friday, while Clinton's running mate Tim Kaine campaigned at the University of Michigan Ann Arbor Michigan earlier in the week.

Clinton's poll drop among the group has been precipitous, and amounts for some of Trump's gains on her.

'Elections aren’t just about who votes but who doesn’t’ vote. And that is especially true for young people like all of you,' the first lady told a cheering crowd in Fairfax, Virginia Friday.

Clinton's running mate, Tim Kaine, campaigned this week at the University of Michigan. The campaign is trying to head off a drop in support among millenials

Bernie Sanders, 75, is older than Clinton, but he has been vouching for the 68 year old Clinton among younger millenial voters, who have been abandoning Clinton in recent polls

Her lead among those 35 and under fell from 24 points late last month to just 5 points in the latest Quinnipiac University poll.

In a Fox News poll, her lead dropped from 27 points to 9 points among the same group, the Wall Street Journal noted.'

The Quinnipiac poll had Clinton beatin Libertarian Party candidate Gary Johnson by just two percentage points among those 18 to 34 years old, 31 to 29 per cent. Green Party candidate Jill Stein was at 15 and Donald Trump was at 26.

The loss of support brought Clinton's lead over Trump in a four-way race down to two points, 41 to 39, compared to 48 to 35 in a hypothetical two-way race.

A Thursday New York Times poll also has Clinton's support dropping with Johnson and Stein in the race.

'I would just simply say to the millennials, to anybody else: Look at the issues ... stay focused on the issues of relevance to your life,’' Sanders said on MSNBC Friday

Clinton's lead among those 35 and under fell from 24 points late last month to just 5 points in the latest Quinnipiac University poll

First lady Michelle Obama campaigns for Clinton at a college in northern Virginia Friday as the campaign tries to stem its slide among millenials

Clinton has been losing millenial voters to Libertarian candidate Gary Johnson

The led Trump by 46 to 44 percent. But with Johnson and Stein included, the two main candidates were tied at 42 per cent.

Clinton is 68 and Trump is 70. Those she is sending out on the trail for her, including the first lady, defeated opponent Senator Bernie Sanders, and Massachusetts Senator Elizabeth Warren, have strong appeal among younger voters.

Clintons lead among millenials has also been dropping in battleground states, including Colorado and Michigan.

Bernie Sanders plugged Clinton among the young on MSNBC Friday, before holding a rally in New York for congressional candidate Zephyr Teachout.

'I would just simply say to the millennials, to anybody else: Look at the issues ... stay focused on the issues of relevance to your life,’' he said.