Leo is one of the few constellations generally considered to actually resemble the mythological character after whom it is named. A relatively compact grouping of stars, Leo is readily recognizable and may be found riding high in the Northern Spring sky from February through June, although it is most noticeable during mid-March evenings. Of all constellations, it is the Lion that usually signals the onset of mild weather in the Northern Hemisphere.

During the dry season in Ancient Egypt, the lions of the desert came close to the Nile Valley when the river flooded, which was known to occur when the Sun was in Leo. Thus, some sources state that this is the origin of the constellation's name. The Ancient Sumarians, Babylonians, Persians, Syrians, Greeks and Romans all recognized this stellar pattern as a Lion. Indeed, Leo has always been credited with solar associations and it was once believed that the Sun rose in Leo at the time of creation. Thus, this constellation was the emblem of fire and heat which nourished the land, particularly associated with all the blessings which rained down from the greatest of the Gods who filled the world with light each day. In this regard, it has been suggested that the Sphinx represents both the Sun and Leo...although there is some controversy surrounding this theory. This constellation is perceived as a horse in the Chinese Zodiac and, in Incan lore, was referred to as a Puma. The Lion was also the tribal sign of Judah and, in the Middle Ages, Leo was referred to as one of Daniel's lions. In ancient times, the sound of thunder, when heard during the Sun's passage through Leo, was taken to herald the imminent death of some great personage.

The head and mane of Leo are formed by an asterism known as the Sickle, which looks rather like a backward or reverse question mark. Alpha Leonis, one of the brightest Spring stars, was named Regulus or "Little King" by the astronomer, Copernicus. It stands at the base of the Sickle and marks its handle. Though generally referred to in modern times as Regulus, this star was bettern known in antiquity as Cor Leoinis or the Lion's Heart. Regulus is a white-blue triple star, sometimes referred to as the "Regulator of Heaven," which does indeed mark the heart of the Lion and was once thought to oversee affairs on Earth as well as ruling the heavens. To the Persians, Regulus was one of the four "Guardian Stars." It is also known as the "Royal Star" and "Kingly Star," being associated in many ways with kings on Earth. Thus, both Regulus and the constellation of Leo itself have become a cherished symbol of monarchy...found on the Royal Coat of Arms in England, for instance. Behind the Sickle, toward the Eastern horizon, three stars form the small triangle which marks the rear of Leo.

Beta Leonis (Leo's second brightest star), also known as Denebola, is a blue star situated in a tuft of hair at the end of the Lion's tail. Gamma Leonis (Leo's third brightest star), also known as Aleibra (Arabaic for "forehead"), is most commonly referred to as Juba, which means "mane." Other notable stars include: (1) Delta Leonis, also known as Zosma (meaning "girdle"), which is located near the Lion's tail and is a triple star, yellow, blue and violet in color; (2) Gamma Leonis, a fine double star; (3) Zeto Leonis and Mu Leonis, often referred to collectively as Al Ashfar or the Lion's Eyebrows; (4) Albeiba or Lion's Mane...the curve or blade of the Sickle; (5) Lambada Leonis, also known as Alterf (which apparently means "extremity"), located at the very tip of the Lion's mouth; and (6) Wolf 359, an extremely faint red dwarf star about the size of Jupiter which is the third closest star to Earth.

This constellation is also associated with a large number of meteor showers, the most famous being the Leonids which are linked to the Comet Tempel-Tuttle. This shower radiates from the region of Gamma Leonis and can be observed around mid-November each year. The fastest of all meteor showers, the Leonids are renown for storms which occur at thirty-three year intervals.

A Northern constellation located between Cancer the Crab and Virgo the Virgin, Leo is also bordered by Hydra the Sea-Serpent, Sextans the Sextant, Coma Berenices the Hair of Bernice, Ursa Major the Great Bear and Lynx the Lynx.