San Diego began as a Spanish fort upon a hill overlooking the bay in 1769. A few years later, a mission was placed about five miles down the valley and another fort was placed on Ballast Point to guard the bay. The soldiers kept law and order and regulated control of international trade, while the friars from the missions taught Christianity to the local natives. This wasn't always easy though. In 1775, there was a native revolt that resulted in the burning of the mission (later rebuilt) and the death of a friar, and there was a battle in 1803 between the Spanish troops at Ballast Point and a US ship called the "Leila Byrd" who had smuggled otter skins out of the area.

By 1821, Mexico had won its independence from Spain and the inhabitants of the old fort on the hill began to spread out and build homes at the foot of the hill, now known as Old Town. One of the inhabitants was Pio Pico, a successful businessman and prominent Mexican politician, who in 1829 made plans in San Diego to take over the Capitol of Alta-California, Los Angeles - the revolt was successful. A few short years later in 1832, he would become Governor pro-tem of Alta-California and secularize the mission lands, making them available to sell. He became Governor in 1845, the same year the United States annexed Texas. Needing money to defend California, he began to sell land. By 1846, a U.S.Naval ship Cyan had docked near the bay and a garrison of marines had raised a United States flag at Old Town's main square, and a battled ensued at San Pasquel Valley between U.S. troops led by General Kerney and "Dragoons" led by Pio Pico's brother Andres.

Now belonging to the United States, entrepreneurs began pouring in and buying land. A new town had sprung up on the grounds of an old Spanish cemetery in the 1850s that is now Downtown San Diego. South of it, an old Spanish ranch was bought, split in two, and became National City and Chula Vista. A lighthouse was built on Point Loma, and the Hotel Del Coronado was built across the bay. Docks were built and roads were paved. Land was reserved for a city park that would later hold the 1915-1916 Panama/California Exposition and the 1936, 1936 California Pacific International Exposition. The U.S. Navy would build bases throughout the county and population exploded. Old wooden structures were soon replaced with skyscrapers, and horse drawn carriages were replaced with cars. In the 1960s, freeways, Qualcomm Stadium, San Diego Sports Arena and the Coronado Bay Bridge were all built. New communities popped up and continued to expand into today.

San Diego began as a Spanish fort upon a hill overlooking the bay in 1769. By 1821, Mexico had won its independence from Spain and the inhabitants of the old fort on the hill began to spread out and build homes at the foot of the hill, now known as Old Town.

During San Diego's Spanish years, soldiers kept law and order and regulated control of international trade, while  friars taught Christianity and farming to the local natives.

There was a battle in 1803 between Spanish cannons at Ballast Point and a US ship called the "Leila Byrd" who had successfully smuggled otter skins out of the area. It was called "The Battle of San Diego Bay", and there were no casualties.

Pio Pico was a successful businessman and prominent Mexican politician who, in 1829, made plans in San Diego to take over the Capitol of Alta-California - the revolt was successful. A few short years later in 1832, he would become Governor pro-tem of Alta-California and secularize the mission lands, making them available to sell.

Qualcomm Stadium, San Diego Sports Arena and the Coronado Bay Bridge were all built in the 1960s.

Pio Pico became Governor of Alta California in 1845, the same year that the United States annexed Texas. Needing money to defend the state, he began to sell land and his brother Andreas would lead a garrison of "Dragoons" who would fight General Kerney's forces in the Battle of San Pasqual.