For the past four months, KCUR's Beyond Our Borders project has examined how the Missouri-Kansas state line affects the lives of those around it.

We've examined the complications that law enforcement faces when responding to crimes along the state line, asked people what they were doing on the state line, and even dove into the political and developmental origins of our bisected metro area.

But one basic question has remained: why is our state line a road?

Mid-America Regional Council senior researcher Jeff Pinkerton says there are only 15 metropolitan areas in the United States that are split by a state line, and most of them are impossible to drive down.

"The vast majority of cities that are divided by a state line are [split by] a river," Pinkerton says. "Here, you have a two lane street where, if you're not paying attention, you might actually cross from one state to another."

So, how did State Line Road come to be? Well, after speaking with several historians, reading countless Kansas City history books, and poring through the Missouri Valley Special Collection archives, we can finally bring you this answer: we don't exactly know.

But don't worry, we have an idea.

Missouri Valley Special Collection / Kansas City Public Library

The earliest mention of State Line Road comes from an 1872 city directory. In those days, State Line Road was simply "State St."

State Street was just a small five block stretch situated in the heart of Kansas City's West Bottoms from 12th Street to 17th Street. At the time, the West Bottoms' stockyards were quickly becoming the center of Kansas City commerce and industry.

Missouri Valley Special Collection Manager Eli Paul believes that the rapid growth of the stockyards was likely the impetus for the creation of what would eventually become State Line Road.

"Some of the early developers [of the West Bottoms] realized that they could do business on both sides of the state line within the same building," Paul says. "They literally straddled the state line so they could conduct different types of business in both states."

Pinkerton also believes that business was crucial to the creation and expansion of State Line Road. He says it's a testament to both Kansas and Missouri that the state line hasn't become a more significant border over time.

"This is a case of economics trumping politics," Pinkerton says. "We always hear talk about one side of the state line poaching businesses, but we've built a region that doesn't really care about arbitrary borders."

In the years after 1872, the city limits of Kansas City, Mo., expanded south and east, and the suburbs on both sides of the state line started to form. And along with Kansas City's borders, State Line Road stretched farther and farther south as well.

This look at the Missouri-Kansas state line is part of KCUR's months-long examination of how geographic borders affect our daily lives in Kansas City. KCUR will go Beyond Our Borders and spark a community conversation through social outreach and innovative journalism.

We will share the history of these lines, how the borders affect the current Kansas City experience and what’s being done to bridge or dissolve them. Be a source for Beyond Our Borders: Share your perspective and experiences on the state line with KCUR.