Before the caucus started, Clinton planned a "victory party" at Drake University in Des Moines.
We checked out the best outfits from party-goers on Monday night.
Some went for classic campaign looks using Hillary's 2016 logo.
"Hillary 2016" t-shirts abounded -- along with sweaters to account for the Iowa cold.
These party-goers got creative, taking Hillary's "fighting for us" slogan literally.
Your squad can't go wrong with big pins explaining your candidate's platform.
"Precinct Leader" pins indicated the real MVPs of the night -- the people who led caucuses to get the vote for Hillary.
A Hillary pin can be fashionable and functional.
Wondering how to make your cute hat even cuter? Add a sticker!
When you're in a bind, accessorize with tape.
Tape can also be used to make giant versions of Hillary's 2016 logo.
The Human Rights Campaign, the LGBT rights group that endorsed Clinton last month, was well represented.
SLAY.
NARAL Pro-Choice America, a pro-abortion group that endorsed Clinton, showed support with t-shirts.
And Planned Parenthood, which -- you guessed it -- also endorsed Hillary, was there in shining colors.
Never underestimate the power of a sensible Planned Parenthood pin.
Some party-goers classed it up...
...while others went all out.
No matter how people chose to accessorize, excitement was in the air as Hillary got past her first challenge on the road to becoming the Democrat's presidential nominee.