Zion is a city in Lake County, Illinois, United States. The population was 22,866 at the 2000 census, and had grown to 24,413 as of 2010.The city was founded in July 1901 by John Alexander Dowie. He also started the Zion Tabernacle of the Christian Catholic Apostolic Church, which was the only church in town. It was built in the early 1900s and burned down in 1937.The city was named after Mount Zion, Israel.According to the 2010 census, Zion has a total area of 9.813 square miles (25.42 km2), of which 9.81 square miles (25.41 km2) (or 99.97%) is land and 0.003 square miles (0.01 km2) (or 0.03%) is water.The city is one of only a few in the world to have ever been completely planned out before building. Dowie modeled the city layout after the Union Flag, because he was originally from Scotland and Australia. In the planning stage he mailed the mayors of many large cities across the world for suggestions on how to design the best city possible.