Earlier this week, President Donald Trump signed an executive order to move forward with the Dakota Access and Keystone XL pipelines, after former President Barack Obama had sought to stop both from being completed under current parameters.
Rousey has posted a pair of stories about the Dakota Access pipeline on her Facebook page recently, before making her appearance at the protests this week.
Rousey has spoken up for political issues in the past, including her endorsement of Democratic candidate Bernie Sanders ahead of the 2016 election, as well as clashing with now President Trump via social media and interviews over the past year.