Northwestern University (NU) is a private research university in Evanston, Illinois, United States. Established in 1851 to serve the historic Northwest Territory, it is the oldest chartered university in Illinois.

Chartered by the Illinois General Assembly in 1851, Northwestern was initially affiliated with the Methodist Episcopal Church but later became non-sectarian. By 1900, the university was the third-largest university in the United States, after Michigan and Harvard. Northwestern became a founding member of the Big Ten Conference in 1896 and joined the Association of American Universities in 1917.

Northwestern is composed of eleven undergraduate, graduate, and professional schools in the fields of management, law, journalism, engineering, medicine, and others. As of 2024, the university had an endowment of $15.6 billion, an annual budget of around $3.3 billion, and research funding of over $1 billion. The university fields 19 intercollegiate athletic teams, the Northwestern Wildcats, which compete in the NCAA Division I in the Big Ten Conference.

As of September 2020, 37 Nobel Prize laureates and 2 Fields Medalists were affiliated with Northwestern as alumni or faculty. In addition, Northwestern has been associated with 47 Pulitzer Prize winners, 23 National Medal of Science winners, 11 National Humanities Medal recipients, 23 MacArthur Fellows, 20 Rhodes Scholars, and 28 Marshall Scholars. Northwestern alumni also include 10 living billionaires, 2 U.S. Supreme Court Justices, and 25 Olympic medalists.

The foundation of Northwestern University can be traced to a meeting on May 31, 1850, of nine prominent Chicago businessmen, Methodist leaders, and attorneys who had formed the idea of establishing a university to serve what had been known from 1787 to 1803 as the Northwest Territory. On January 28, 1851, the Illinois General Assembly granted a charter to the Trustees of the North-Western University, making it the first chartered university in Illinois. The school's nine founders, all of whom were Methodists (three of them ministers), knelt in prayer and worship before launching their first organizational meeting. Although they affiliated the university with the Methodist Episcopal Church, they favored a non-sectarian admissions policy, believing that Northwestern should serve all people in the newly developing territory by bettering the economy in Evanston.

John Evans, for whom Evanston is named, bought 379 acres (153 ha) of land along Lake Michigan in 1853, and Philo Judson developed plans for what would become the city of Evanston, Illinois. The first building, Old College, opened on November 5, 1855. To raise funds for its construction, Northwestern sold $100 "perpetual scholarships" entitling the purchaser and his heirs to free tuition. Another building, University Hall, was built in 1869 of the same Joliet limestone as the Chicago Water Tower, also built in 1869, one of the few buildings in the heart of Chicago to survive the Great Chicago Fire of 1871.

In 1873 Evanston College for Ladies merged with Northwestern. Frances Willard, who later gained fame as a suffragette and as one of the founders of the Woman's Christian Temperance Union, became the school's first dean of women (Willard Residential College, built in 1938, honors her name). Northwestern admitted its first female students in 1869, and the first woman graduated in 1874. Northwestern fielded its first intercollegiate football team in 1882, later becoming a founding member of the Big Ten Conference. In the 1870s and 1880s, Northwestern affiliated itself with already existing schools of law, medicine, and dentistry in Chicago. As the university's enrollments grew, these professional schools were integrated with the undergraduate college in Evanston. The result was a modern research university combining professional, graduate, and undergraduate programs, which gave equal weight to teaching and research.

By the turn of the century, Northwestern had grown in stature to become the third-largest university in the United States after Harvard University and the University of Michigan. Under Walter Dill Scott's presidency from 1920 to 1939, Northwestern began construction of an integrated campus in Chicago designed by James Gamble Rogers, noted for his Collegiate Gothic architecture, to house the professional schools. In addition, James Gamble Rogers designed a library in accordance with the gothic architectural style on the Evanston campus in order to make use of the $1 million donated to the school after the death of Charles Deering. This library is named in memory of him and its design was inspired by Cambridge University's King's College Chapel. The university also established the Kellogg School of Management and built several prominent buildings on the Evanston campus, including Dyche Stadium, now named Ryan Field, among others. In the 1920s, Northwestern became one of the first six universities in the United States to establish a Naval Reserve Officers Training Corps (NROTC). In 1939, Northwestern hosted the first-ever NCAA Division I men's basketball championship game in the original Patten Gymnasium, which was later demolished and relocated farther north, along with the Dearborn Observatory, to make room for the Technological Institute.^{[citation needed]}