by the 1850s and 1860s new migration had spread settlements to the middle section of the country including most notably the state of?

To determine which state was most notably settled during the 1850s and 1860s in the middle section of the country, you can follow these steps:

1. Identify the middle section of the country: The middle section generally refers to the Midwest region of the United States, which includes states like Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, and Kansas.

2. Find the state that experienced notable settlement during the 1850s and 1860s: During this time period, there was a significant influx of settlers in various states due to factors such as the Homestead Act of 1862, the California Gold Rush, and the opening of new territories for settlement. Among the states in the middle section, the most notable for new migration during this period was Kansas.

Kansas became the center of attention due to the conflict over the expansion of slavery, which escalated into violent clashes known as "Bleeding Kansas." People from both the North and the South settled in Kansas to sway the outcome of the slavery debate. The state's population grew rapidly as a result of this migration.

Therefore, the state that was most notably settled during the 1850s and 1860s in the middle section of the country is Kansas.