Question

Proslavery settlers who came to Kansas from Missouri in the 1800s were known as

Answer 1

I'm pretty sure it would be "Border Ruffians" 

Answer 2

Answer:

Proslavery settlers who came to Kansas from Missouri in the 1800s were known as  Border Ruffians.

Explanation:

The Border Ruffians were a private army raised by the big slave owners of Missouri, involved in the bloody events of Bleeding Kansas, during a political race between abolitionists and slavers to determine whether Kansas, created in 1861 as a state, with two representatives in the Senate, would be a slave state or not.

Missouri slave owners actively campaigned for the United States to remain a slave country. They created political groups called the Border Ruffians, that crossed the west bank of Missouri to the neighboring lands of the Kansas Territory, where they were engaged in the armed struggle against abolitionists like John Brown.  In March 1855, the Missouri Border Ruffians invaded Kansas during the territory's first election and imposed a pro-slavery legislature.