Elmhurst is a city mostly in DuPage County and overlapping into Cook County in the U.S. state of Illinois, and a western suburb of Chicago.

Members of the Potawatomi Native American people, who settled along Salt Creek just south of where the city would develop, are the earliest known settlers of the Elmhurst area. Around 1836, European-American immigrants settled on tracts of land along the same creek. At what would become Elmhurst City Centre, a native of Ohio named Gerry Bates established a community on a tract of "treeless land" in 1842.

The following year, Hill Cottage Tavern opened where St. Charles Road and Cottage Hill Avenue presently intersect. In 1845, the community was officially named Cottage Hill when a post office was established. Four years later, the Galena and Chicago Union Railroad was given right-of-way through the community, giving farmers easier access to Chicago. The first Elmhurst railroad station was built in 1894. The community changed its name to Elmhurst in 1869, and in 1871 Elmhurst University was organized. The land for Elmhurst University was gifted by prominent resident Thomas Barbour Bryan. Bryan (often referred to as the "Father of Elmhurst") played an important role in the development of the town, and has been as the one responsible for renaming the town.

Elmhurst was incorporated as a village in 1882, with a population between 723 and 1,050, and legal boundaries of St. Charles Road to North Avenue, and one half mile west and one quarter mile east of York Street. Elmhurst Memorial Hospital was founded in 1926 as the first hospital in DuPage County.

The Memorial Parade has run every Memorial Day since 1918. The annual Elmhurst St. Patrick's Day Parade continues to be the third largest parade of that sort in the Chicago area, following the more famous parades downtown and on the city's South Side.

Since 1964, it has been home to Elmhurst CRC, one of the largest congregations of the Christian Reformed Church in North America.

The Keebler Company's corporate headquarters was in Elmhurst until 2001, when the Kellogg Company purchased the company. The city is home to the headquarters of Sunshine Biscuits and McMaster-Carr Supply Co.

In 2014, Family Circle magazine ranked Elmhurst as one of the "Ten Best U.S. Towns for Families".

According to the 2021 census gazetteer files, Elmhurst has a total area of 10.28 square miles (26.63 km2), of which 10.22 square miles (26.47 km2) (or 99.42%) is land and 0.06 square miles (0.16 km2) (or 0.58%) is water.

Due to local topography, the town has had a tendency to flood in the past after large rainfalls; the city is currently undertaking a large effort to mitigate future flooding.

As of the 2020 census there were 45,786 people, 16,808 households, and 12,110 families residing in the city. The population density was 4,454.76 inhabitants per square mile (1,719.99/km2). There were 17,260 housing units at an average density of 1,679.32 per square mile (648.39/km2). The racial makeup of the city was 80.47% White, 6.51% Asian, 2.14% African American, 0.26% Native American, 0.02% Pacific Islander, 2.92% from other races, and 7.67% from two or more races. Hispanic or Latino of any race were 9.32% of the population.

There were 16,808 households, out of which 35.8% had children under the age of 18 living with them, 63.37% were married couples living together, 6.49% had a female householder with no husband present, and 27.95% were non-families. 24.44% of all households were made up of individuals, and 13.61% had someone living alone who was 65 years of age or older. The average household size was 3.26 and the average family size was 2.70.

The city's age distribution consisted of 25.1% under the age of 18, 8.6% from 18 to 24, 21.3% from 25 to 44, 28.4% from 45 to 64, and 16.5% who were 65 years of age or older. The median age was 40.7 years. For every 100 females, there were 96.9 males. For every 100 females age 18 and over, there were 94.8 males.

The median income for a household in the city was $123,869, and the median income for a family was $148,663. Males had a median income of $83,584 versus $46,935 for females. The per capita income for the city was $59,911. About 2.1% of families and 3.4% of the population were below the poverty line, including 3.0% of those under age 18 and 4.5% of those age 65 or over.

According to Elmhurst's 2017 Comprehensive Annual Financial Report, the top employers in the city are:

Timeline for Elmhurst's leadership:

Elmhurst University is a local college of the area. It is a four-year private liberal arts college affiliated with the United Church of Christ.

School districts serving Elmhurst include:

Private schools:

Elmhurst is served by Pace buses, and the Metra Union Pacific West Line through the Elmhurst station. The Union Pacific Railroad has freight service on the Metra line and the Canadian National Railway serves the former Illinois Central line south of the Metra line, known as the Freeport Subdivision. O'Hare International Airport is roughly 18 minutes from Elmhurst, and Chicago Midway International Airport is roughly 33 minutes from Elmhurst.

During the summers and December, Elmhurst also has the "Elmhurst Express Trolley", a free weekend trolley that connects downtown Elmhurst to the Spring Road businesses and the Elmhurst Public Library. It runs Friday-Saturday and the $40,000 cost comes out of visiting and tourism fund.

Elmhurst was previously served by the Chicago Aurora and Elgin Railroad, an electric interurban rail line. The station opened in 1902 as "South Elmhurst" until being renamed to "York St." The station closed in 1959 after the CA&E ceased operations. The Illinois Prairie Path now runs over the former line.