The Vatican City is a roughly triangular tract of land within Rome, on the west bank of the Tiber River and west of the Castel Sant'Angelo. In its southeast corner is the piazza of Saint Peter's Church, surrounded by the splendid colonnade. North of the piazza is a quadrangular area containing administrative buildings and the Belvedere Park. West of Belvedere Park are the pontifical palaces, and beyond the palaces lie the Vatican Gardens, which make up half the area of the little state. The Leonine Wall forms the western and southern boundaries.

In the city of Rome are certain important basilicas, churches, and other buildings to which the Italian government extends the rights of extraterritoriality and tax exemption but not papal sovereignty. The basilicas include San Giovanni in Laterno (St. John Lateran), Santa Maria Maggiore (St. Mary Major), and San Paolo fuori le Mura (St. Paul outside the Walls). The palace of San Callisto at the foot of the Janiculum also shares the immunity of the Vatican, as does the papal summer residence at Castel Gandolfo, in the Alban Hills outside Rome.

Vatican City has its own citizenship, issues its own currency and postage stamps, and has its own flag and a large diplomatic corps. It is open to visitors all year, and the pope receives callers in public and private audiences. It has its own newspaper (Osservatore Romano), railroad station, and broadcasting facility (first established by Marconi under Pius XI). The seven Vatican universities, including the Pontifical Gregorian Univ., are located in Rome. The political freedom of the Vatican is guaranteed and protected by Italy.

The civil government of Vatican City is headed by the cardinal president of the Pontifical Commission for Vatican City, which is the state's legislature; the state is governed under the Fundamental Law of 2000. The legal system is based on canon law, and the courts are part of the judicial system of the church. The only court special to Vatican City is a court of first instance for civil and criminal cases arising in the city.

The Vatican is above all the seat of the central government of the Roman Catholic Church. Because of the papacy's vast interest in temporal as well as spiritual affairs, an elaborate bureaucracy has been developed over the course of centuries. The pope governs the church with the College of Cardinals. He may act as he chooses without their consent, but in practice he relies on the cardinals for advice as well as for administration of the church government. The whole administrative body surrounding the pope and responsible to him is called the Curia Romana.

The papal court long had all the characteristics of a royal court, such as elaborate rituals and uniforms, and complex rules of precedence; however, since the reign of Pope John XXIII (1958–63) and the Second Vatican Council, many of the Vatican ceremonies have been greatly simplified. The bodyguard of the pope is the corps of Swiss Guards, founded in the 16th cent. and made up of a small group of Roman Catholic Swiss. Its members wear the splendid Renaissance uniforms designed by Michelangelo.

The Vatican palaces are an irregular mass of three-story and four-story buildings, built on long, plain lines and broken by additions and alterations. The papal residence and offices occupy the portion near the colonnade, and the rest is given over to museums and the Vatican Library. The Vatican museums are among the most important in the world; they are the Museo Pio-Clementino, founded in the 18th cent. and containing one of the world's great collections of antiquities; the Chiaramonti Museum, founded in the early 19th cent. and holding a collection of Greek sculptures and Renaissance imitations; the Braccio Nuovo, considered by many to be the most beautiful of all the museums; the Egyptian Museum and the Etruscan Museum, opposite the Braccio Nuovo; and the Pinacoteca Vaticana (opened in 1932), which contains paintings by Giotto, Guercino, Caravaggio, Poussin, and others.

The museums, however, house only part of the Vatican's treasure, for many of the Renaissance and modern paintings are found in the galleries surrounding the various courtyards, such as the Cortile del Belvedere and the Cortile San Damasco. Adjoining the Cortile San Damasco is the building containing the Borgia apartments on the first floor and the Raphael rooms on the second. The works of Raphael and his followers in the building make it one of the most famous artistic monuments in the world. The Vatican Library lies all along the western side of the Giardino della Pigna and Cortile del Belvedere. It is one of the world's richest repositories of ancient and medieval manuscripts in many languages. The principal chapel in the Vatican is the Sistine Chapel, the ceiling of which was painted (1508–12) by Michelangelo.

The history of the Vatican as a papal residence dates from the 5th cent., when, after Emperor Constantine I had built the basilica of St. Peter's, Pope Symmachus built a palace nearby. The pope usually resided in the Lateran Palace until the Babylonian captivity (14th cent.) in Avignon, France. After the return of the papacy to Rome (1377) the Vatican became the usual residence. The Renaissance popes, principally Sixtus IV, Innocent VIII, Alexander VI, Julius II, Leo X, and Clement VII, were great patrons of the arts, and it was they who began to assemble the great collections and to construct the wonderful galleries. Gregory XIII and Sixtus V spent huge sums on the Vatican and also began the Quirinal, a palace that served as the papal residence from the 17th to the 19th cent., was the Italian royal palace from 1870 to 1946, and is now the home of the president of Italy.