Peoria is a city in and the county seat of Peoria County, Illinois, United States, and the largest city on the Illinois River. Established in 1691 by the French explorer Henri de Tonti, Peoria is the oldest European settlement in Illinois, and is named after the Peoria tribe. As of the 2010 census, the city was the seventh-most populated in Illinois (and the third largest outside of the Chicago metropolitan area), with a population of 115,007. The Peoria Metropolitan Statistical Area had a population of 373,590 in 2011. Peoria had a population of 118,943 in 2010, when far northern Peoria was also included. Peoria is, until later in 2017 when a move of some executive and support staff (in the end, about 300) to Chicago will begin, the global and national headquarters for Caterpillar Inc., one of the 30 companies composing the Dow Jones Industrial Average, and listed on the Fortune 100. Around 12,000 jobs will still remain in the Peoria area. Bloomington is a city in Illinois, United States and the county seat of McLean County. It is adjacent to Normal, and is the more populous of the two principal municipalities of the Bloomington-Normal metropolitan area.The 2010 census showed the city had a population of 76,610, making it the 12th most populated city in Illinois, and the fifth-most populous city in the state outside of the Chicago Metropolitan Area. Combined with Normal, the twin cities have a population of roughly 130,000. Rock Island is a city in and the county seat of Rock Island County, Illinois, United States. The original Rock Island, from which the city name is derived, is the largest island on the Mississippi River. It is now called Arsenal Island. The population was 39,018 at the 2010 census. Located on the Mississippi River, it is one of the Quad Cities, along with neighboring Moline, East Moline, and the Iowa cities of Davenport and Bettendorf. The Quad Cities has a population of about 380,000. The city is home to Rock Island Arsenal, the largest government-owned weapons manufacturing arsenal in the US, which employs 6,000 people. There’s a wide variety of housing available in Rock Island including historic homes, new downtown condos, new construction in the heart of the city, and wooded retreats. The Rock Island-Milan School District, Rockridge School District (southwest portion of city) along with private schools, serve the city. The District (Downtown Rock Island) has art galleries and theaters, nightclubs and coffee shops, and restaurants of all flavors. Golf courses, parks, a casino, botanical center, marina, historic tours, bike paths, and festivals offer entertainment opportunities.In 2015 Rock Island was ranked the 32nd “Best Small City” in the country based on economic health, affordability, and quality of life. Rock Island made the list of the nations “25 Most Affordable Housing Markets”, a ranking released by 24/7 Wall Street.