INTERESTING FACTS: Originally named for Hugh Mercer, a doctor during the American Revolution who died in battle. The land in Mercer County was originally meant for veterans of the War of 1812.
- Aledo: Population – 3,643. Aledo is the county seat of Mercer County. The town grew during the 1850s with construction of the railroad. Aledo is also home to country music singers Suzy Bogguss and Margo Price. Aledo was the former home to William & Vashti College from 1908-1917. The town hosts 2 major festivals – Antique Days (in September) and Rhubarb Fest (in June)
- Viola: Population – 955.
- Alexis: Population – 863. Alexis is actually part of Warren and Mercer County (499 in Warren & 364 in Mercer). The town was named for Russian ambassador Alexei Alexandrovich (son of emperor Alexander II) who toured the midwest (the town was originally named Alexandria). The largest employer is Alexis Fire Equipment.
- Matherville: Population – 772. Located about 20 miles south of Rock Island. The town was named for George Mather who sold articles to railroad workers so they would get the town named after him.
- Windsor: Population – 748.
- New Boston: Population – 683. Located on the border of the Mississippi River, just 5 miles south of Lock and Dam #17. Much of the area surrounding New Boston is part of the Port Louisa National Wildlife Refuge which largely protects migratory birds.
- Sherrard: Population – 640. Original land was purchased by David Sherrard in 1854 for $2,200. In 1894 the land was transferred to the Coal Valley Mining Company. The town boomed until the mine closed in 1918. The village was considered fairly progressive as it had electricity and telephones sooner than most. The town boomed again after WWII with 4 grocery stores, 2 restaurants, an automobile dealer, hardware store and other businesses. The population somewhat declined in the 1980s and remained around 700 in the 1990s.
- Keithsburg: Population – 609. Named for a pioneer settler, this town originally had over 1,000 people in 1950. The town suffered a massive flood in 1993 and in 2008 two massive levees broke which caused further flooding.
- Reynolds: Population – 508.
- Joy: Population – 417. Joy County is home to Mercer Junior High School which once was Westmer High School.
- Seaton: Population – 222.
- North Henderson: Population – 187. Home to Karl Swanson who was once the oldest living former Major League Baseball player, a 2nd baseman for the Chicago White Sox. He was also the only major leaguer to live through the entire 20th century (1900-2002).