Editing Columbia, Pennsylvania (section)

====Economic decline====
The start of the 20th century brought economic challenge to Columbia as local industries declined. The lumber industry eventually disappeared as surrounding woodlands became depleted. As Chestnut Hill iron ores became scarce as well, the iron furnaces shut down. Eventually, the [[steel mill|steel]] [[rolling (metalworking)|rolling mills]] also ceased operation. In 1906, the Pennsylvania Railroad opened a new facility in [[Enola, Pennsylvania|Enola]], across the river from Harrisburg, which decreased the significance of Columbia's railroad. By 1920, the population had dropped over 10% to 10,836.

The [[Great Depression in the United States|Great Depression]] accelerated Columbia's economic slide. The Pennsylvania Railroad's service to the north and the south was eliminated. [[World War II]] increased employment, but did not bring long-term prosperity to the borough.

By 1960, population had returned to its 1900 level. In 1965 a detailed study of Columbia's basic strengths and weaknesses was released, but its suggestions went mostly unheeded. The [[Wright's Ferry Bridge]], which opened in 1972, only served to divert traffic around Columbia. The growth and prosperity experienced in some Lancaster County towns bypassed Columbia for the remainder of the 20th century. Although the [[United States Census Bureau]] reported that as of the last year of the 20th century, the population of Columbia had been only 10,311 people, by 2010 this figure had grown to 10,400.