1) On March 15, 1792, Kentucky became the 15th state to join the United States of America. The decision was made by the United States Congress to admit Kentucky as a state after it had been a part of Virginia since its founding in 1776.

2) In 1820, a steamboat called the “Orleans” made its appearance on the Ohio River near Louisville. This was a significant milestone, as steamboats became a popular mode of transportation for goods and people in Kentucky during the 19th century.

3) March 15, 1896 saw the birth of John B. Hood, a Civil War Confederate general born in Owingsville, Kentucky. Hood was known for his aggressive tactics during battles such as Gettysburg and Chickamauga, which ultimately led to his defeat.

4) In 1940, Kentucky's Mammoth Cave National Park was officially established. The park is home to the world's largest cave system, with more than 400 miles of explored cave passageways.

5) On March 15, 1981, the historic "Big Four" Railroad Bridge spanning the Ohio River between Jeffersonville, Indiana and Louisville, Kentucky was officially reopened to pedestrian traffic after renovations. The bridge, which was built in 1895, is now a popular tourist attraction and pedestrian walkway.