Moraga is located at 37°50'06" North, 122°07'47" West, at an elevation of 499 feet (152 m). It is located adjacent to the cities of Lafayette and Orinda, as well as the unincorporated community of Canyon. Other nearby cities include Walnut Creek, Oakland, San Francisco, Concord and Berkeley.
According to the United States Census Bureau, the town has a total area of 9.4 square miles (24 km2), of which, 9.4 square miles (24 km2) is land and 0.09% is water. Originally Moraga was abundant with pears, but, over the years more houses have been built and it is losing its pear trees. The old orchards are now reduced to but a few acres. Rimer Ranch has begun planting new fruit trees on the south edge of town.
Moraga is in a valley, surrounded by rolling hills (green in the winter, brown in the summer) and grazing cows. Residents enjoy walking or biking many trails in the Lamorinda area. Large sections of the Lafayette-Moraga Regional Trail pass through the town.
Joaquin Moraga was the grandson of José Joaquín Moraga, builder of the Presidio of San Francisco and founder of the pueblo that grew into the city of San Jose. Joaquin's father Gabriel Moraga was also a soldier, and an early explorer who named many of the state's rivers, including the Sacramento and San Joaquin.
Moraga is located on the 1835 Mexican Land Grant Rancho Laguna de los Palos Colorados given to Joaquin Moraga and his cousin, Juan Bernal. Part of that grant was the property today known as Moraga Ranch. The Moraga Adobe has been preserved, and is located in neighboring Orinda. Joaquin Moraga Intermediate School, a middle school in Moraga, bears his name.