Reidsville, was permanently renamed Bartow in honor of Francis S. Bartow, the first Confederate brigade commander to die during the war. Bartow recovered slowly from the war. The first Polk County Courthouse was built in 1867, which firmly established the city as county seat. Although Florida formally rejoined the union in 1868, the Reconstruction era did not end in Florida until 1877. The 1880s and 1890s were a period of growth for the city of Bartow; from 1880 to 1900, the city would grow from 386 residents to 1,983. On July 1, 1882 the town was incorporated as a city. In 1885, the Florida Southern Railroad, a north-south route from North Florida to Southwest Florida opened in Bartow. A year later, the Bartow Branch of the South Florida Railroad, connecting Tampa and Orlando, was completed. The railroads were catalysts for growth of the area; during the Spanish–American War, the Bartow rail yards became a crucial part of the supply line directed at US troops in Cuba. In 1887, Summerlin Institute, the first brick schoolhouse south of Jacksonville, was built. By the turn of the century, Bartow had become the most populous city south of Tampa on the Florida peninsula – larger than Miami or West Palm Beach. As the city grew, a number of industries moved into the Bartow area. In the first few decades of the 1900s, thousands of acres of land around the city were purchased by the phosphate industry. Bartow would become the hub of the largest phosphate industry in the United States. Polk County was the leading citrus county in the United States for much of the 20th century and the city has several large groves. In 1941, the city built an airport northeast of town. The airport was taken over by the federal government during World War II and was the training location for many Army Air Corps pilots during the war. The airport was returned to the city in 1967 and renamed as Bartow Municipal Airport. For most of the 20th century, Bartow's growth was modest, especially in comparison to the rest of the county and state. While other cities in Polk County aggressively annexed adjacent land and allowed rapid growth, the government of Bartow generally took a more cautious approach. Bartow's growth was also limited because most of the land surrounding the city was owned by phosphate mining companies, making residential growth impractical.