Collinsville is a city located mainly in Madison County

Madison County, Illinois

Madison County is a county located in the U.S. state of Illinois. Madison County is part of the Metro-East region of the St. Louis Metro Area. According to the 2010 census, it has a population of 269,282, which is an increase of 4.0% from 258,941 in 2000. The county seat is Edwardsville, home to...

, and partially in St. Clair County

St. Clair County, Illinois

St. Clair County is a county located in the U.S. state of Illinois. In 1970, the U.S. Census Bureau placed the mean center of U.S. population in St. Clair County. According to the 2010 census, it has a population of 270,056, which is an increase of 5.5% from 256,082 in 2000. Its county seat is...

, both in Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. As of the 2010 census, the city had a population of 26,016. Collinsville is approximately 12 miles from St. Louis, Missouri

St. Louis, Missouri

St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

 and is considered part of that city's Metro-East

Metro-East

Metro East is a region in Illinois that comprises the eastern suburbs of St. Louis, Missouri, United States. It encompasses five Southern Illinois counties in the St. Louis Metropolitan Statistical Area. The region's most populated city is Belleville at 45,000 residents...

 area. Famously, it is the home of the Brooks Catsup Bottle Water Tower

Brooks Catsup Bottle Water Tower

The Brooks Catsup Bottle Water Tower is a water tower south of Collinsville, Illinois. It is claimed to be the largest catsup bottle in the world. As a prime example of mid-20th-century novelty architecture, it is listed on the National Register of Historic Places...

—the world's largest ketchup

Ketchup

Ketchup is a sweet-and-tangy condiment typically made from tomatoes, vinegar, sugar or high-fructose corn syrup and an assortment of...

 bottle—and is the world's horseradish

Horseradish

Horseradish is a perennial plant of the Brassicaceae family, which also includes mustard, wasabi, broccoli, and cabbages. The plant is probably native to south eastern Europe and the Arab World , but is popular around the world today...

 capital http://www.saucemagazine.com/article/5/23.
Collinsville is located at 38°40′28"N 89°59′43"W (38.674398, -89.995402).