On Sunday, a large crowd filled the upstairs room of Lecompton’s Constitution Hall State Historic Site, possibly the oldest wooden structure in the state at 156 years old, to celebrate the 151st Kansas Day.

The museum kicked off this year’s “Bleeding Kansas” lecture series with Todd Mildfelt’s presentation on the Underground Railroad in Kansas.

The audience lined the back wall of the room and stretched into the outside hallway to listen to the lecture. Among the listeners were local historians, students and state Sen. Marci Francisco, D-Lawrence.

“I wouldn’t want to be anywhere else on Kansas Day,” Mildfelt said to the crowd.

Mildfelt is a historian and teacher from Richmond, about 15 miles south of Ottawa. He has taught history and math for 29 years and wrote two books about the anti-slavery movement in Kansas.

His lecture on Sunday emphasized the importance of the Underground Railroad in Kansas. Because only 900 slaves escaped through Kansas — an estimated 40,000 to 100,000 escaped throughout the nation — Mildfelt said historians tend to underestimate the impact the state’s Underground Railroad had on the nation.

“Failure to spread slavery to Kansas helped spur Southern leaders to action,” he said.

While many Kansans assisted runaway slaves out of moral beliefs, Mildfelt said abolitionists used the Underground Railroad as a political weapon against their Eastern and Southern adversaries. As the border struggle continued, Mildfelt said, leaders wanted fugitive slaves to stay in Kansas instead of traveling to Canada. This move openly defied the Fugitive Slave Act, the federal law that forbid harboring slaves.

Mildfelt said the Border War with Missouri — also known as Bleeding Kansas — radicalized the state’s Underground Railroad and made it particularly violent. In fact, he said Kansas leaders wanted to arm every slave with a revolver and a Bowie knife.

He also cleared common misconceptions of tunnels and false-bottom wagons being used. Although a few did exist, he said slaves usually hid in houses for weeks on end as abolitionists raised money for the trip north.

Lesa Brose, a Valley Falls resident, said she comes to the lecture series every year.

“Hearing these stories and trying to imagine what these people went through, that’s what I enjoy,” Brose said.

The “Bleeding Kansas” lecture series will continue for the next four weeks at 2 p.m. each Sunday. The next presentation will be on James Lane, a Civil War general and U.S. senator, and the namesake of Lane University in Lecompton.